Contents 1 Experimental determination 2 Recent revision aimed at more precise determination - ISO 226:2003 3 Side versus frontal presentation 4 Headphones versus loudspeaker testing 5 Relevance to sound level measurement and noise measurement 6 See also 7 Notes 8 References 9 External links


Experimental determination[edit] The human auditory system is sensitive to frequencies from about 20 Hz to a maximum of around 22,000 Hz, although the upper hearing limit decreases with age. Within this range, the human ear is most sensitive between 2 and 5 kHz, largely due to the resonance of the ear canal and the transfer function of the ossicles of the middle ear. Fletcher and Munson first measured equal-loudness contours using headphones (1933). In their study, test subjects listened to pure tones at various frequencies and over 10 dB increments in stimulus intensity. For each frequency and intensity, the listener also listened to a reference tone at 1000 Hz. Fletcher and Munson adjusted the reference tone until the listener perceived that it was the same loudness as the test tone. Loudness, being a psychological quantity, is difficult to measure, so Fletcher and Munson averaged their results over many test subjects to derive reasonable averages. The lowest equal-loudness contour represents the quietest audible tone—the absolute threshold of hearing. The highest contour is the threshold of pain. Churcher and King carried out a second determination in 1937, but their results and Fletcher and Munson's showed considerable discrepancies over parts of the auditory diagram.[1] In 1956 Robinson and Dadson produced a new experimental determination that they believed was more accurate. It became the basis for a standard (ISO 226) that was considered definitive until 2003, when ISO revised the standard on the basis of recent assessments by research groups worldwide.


Recent revision aimed at more precise determination - ISO 226:2003[edit] Perceived discrepancies between early and more recent determinations led the International Organization for Standardization (ISO) to revise the standard curves in ISO 226. They did this in response to recommendations in a study coordinated by the Research Institute of Electrical Communication, Tohoku University, Japan. The study produced new curves by combining the results of several studies—by researchers in Japan, Germany, Denmark, UK, and USA. (Japan was the greatest contributor with about 40% of the data.) This has resulted in the recent acceptance of a new set of curves standardized as ISO 226:2003. The report comments on the surprisingly large differences, and the fact that the original Fletcher-Munson contours are in better agreement with recent results than the Robinson-Dadson, which appear to differ by as much as 10–15 dB especially in the low-frequency region, for reasons not explained.[2]


Side versus frontal presentation[edit] Equal-loudness curves derived using headphones are valid only for the special case of what is called side-presentation, which is not how we normally hear. Real-life sounds arrive as planar wavefronts, if from a reasonably distant source. If the source of sound is directly in front of the listener, then both ears receive equal intensity, but at frequencies above about 1 kHz the sound that enters the ear canal is partially reduced by the masking effect of the head, and also highly dependent on reflection off the pinna (outer ear). Off-centre sounds result in increased head masking at one ear, and subtle changes in the effect of the pinna, especially at the other ear. This combined effect of head-masking and pinna reflection is quantified in a set of curves in three-dimensional space referred to as head-related transfer functions (HRTFs). Frontal presentation is now regarded as preferable when deriving equal-loudness contours, and the latest ISO standard is specifically based on frontal and central presentation. The Robinson-Dadson determination used loudspeakers, and for a long time the difference from the Fletcher-Munson curves was explained partly on the basis that the latter used headphones. However, the ISO report actually lists the latter as using "compensated" headphones, though it doesn't make clear how Robinson-Dadson achieved that.


Headphones versus loudspeaker testing[edit] This section does not cite any sources. Please help improve this section by adding citations to reliable sources. Unsourced material may be challenged and removed. (October 2015) (Learn how and when to remove this template message) Good headphones, well sealed to the ear, provide a flat low-frequency pressure response to the ear canal, with low distortion even at high intensities. At low frequencies the ear is purely pressure-sensitive, and the cavity formed between headphones and ear is too small to introduce modifying resonances. Headphone testing is therefore a good way to derive equal-loudness contours below about 500 Hz, though reservations have been expressed about the validity of headphone measurements when determining the actual threshold of hearing, based on observation that closing off the ear canal produces increased sensitivity to the sound of blood flow within the ear, which the brain appears to mask in normal listening conditions[citation needed]. At high frequencies, headphone measurement gets unreliable, and the various resonances of pinnae (outer ears) and ear canals are severely affected by proximity to the headphone cavity. With speakers, the opposite is true. A flat low-frequency response is hard to obtain—except in free space high above ground, or in a very large and anechoic chamber that is free from reflections down to 20 Hz. Until recently,[when?] it was not possible to achieve high levels at frequencies down to 20 Hz without high levels of harmonic distortion. Even today, the best speakers are likely to generate around 1 to 3% of total harmonic distortion, corresponding to 30 to 40 dB below fundamental. This is not good enough, given the steep rise in loudness (rising to as much as 24 dB per octave) with frequency revealed by the equal-loudness curves below about 100 Hz. A good experimenter must ensure that trial subjects really hear the fundamental and not harmonics—especially the third harmonic, which is especially strong as a speaker cone's travel becomes limited as its suspension reaches the limit of compliance. A possible way around the problem is to use acoustic filtering, such as by resonant cavity, in the speaker setup. A flat free-field high-frequency response up to 20 kHz, on the other hand, is comparatively easy to achieve with modern speakers on-axis. These effects must be considered when comparing results of various attempts to measure equal-loudness contours.


Relevance to sound level measurement and noise measurement[edit] The A-weighting curve—in widespread use for noise measurement—is said to have been based on the 40-phon Fletcher–Munson curve. However, research in the 1960s demonstrated that determinations of equal-loudness made using pure tones are not directly relevant to our perception of noise.[3] This is because the cochlea in our inner ear analyzes sounds in terms of spectral content, each "hair-cell" responding to a narrow band of frequencies known as a critical band. The high-frequency bands are wider in absolute terms than the low frequency bands, and therefore "collect" proportionately more power from a noise source. However, when more than one critical band is stimulated, the outputs of the brain sum the various bands to produce an impression of loudness. For these reasons Equal-loudness curves derived using noise bands show an upwards tilt above 1 kHz and a downward tilt below 1 kHz when compared to the curves derived using pure tones. Various weighting curves were derived in the 1960s, in particular as part of the DIN 4550 standard for audio quality measurement, which differed from the A-weighting curve, showing more of a peak around 6 kHz. These gave a more meaningful subjective measure of noise on audio equipment, especially on the newly invented compact cassette tape recorders with Dolby noise reduction, which were characterised by a noise spectrum dominated by high frequencies. BBC Research conducted listening trials in an attempt to find the best weighting curve and rectifier combination for use when measuring noise in broadcast equipment, examining the various new weighting curves in the context of noise rather than tones, confirming that they were much more valid than A-weighting when attempting to measure the subjective loudness of noise. This work also investigated the response of human hearing to tone-bursts, clicks, pink noise and a variety of other sounds that, because of their brief impulsive nature, do not give the ear and brain sufficient time to respond. The results were reported in BBC Research Report EL-17 1968/8 entitled The Assessment of Noise in Audio Frequency Circuits. The ITU-R 468 noise weighting curve, originally proposed in CCIR recommendation 468, but later adopted by numerous standards bodies (IEC, BSI, JIS, ITU) was based on the research, and incorporates a special Quasi-peak detector to account for our reduced sensitivity to short bursts and clicks.[4] It is widely used by Broadcasters and audio professionals when they measure noise on broadcast paths and audio equipment, so they can subjectively compare equipment types with different noise spectra and characteristics.


See also[edit] Audiogram A-weighting CCIR (ITU) 468 Noise Weighting dB(A) Listener fatigue Pure tone audiometry Sound level meter Luminosity function, the same concept in vision


Notes[edit] ^ D W Robinson et al., "A re-determination of the equal-loudness relations for pure tones", Br. J. Appl. Phys. 7 (1956), pp.166–181. ^ Yôiti Suzuki, et al., "Precise and Full-range Determination of Two-dimensional Equal Loudness Contours" Archived 2007-09-27 at the Wayback Machine.. ^ Bauer, B., Torick, E., "Researches in loudness measurement", IEEE Transactions on Audio and Electroacoustics, Vol. 14:3 (Sep 1966), pp.141–151. ^ Ken’ichiro Masaoka, Kazuho Ono, and Setsu Komiyama, "A measurement of equal-loudness level contours for tone burst", Acoustical Science and Technology, Vol. 22 (2001) , No. 1 pp.35–39.


References[edit] Audio Engineer's Reference Book, 2nd Ed., 1999, edited Michael Talbot Smith, Focal Press. An Introduction to the Psychology of Hearing 5th ed, Brian C.J. Moore, Elsevier Press.


External links[edit] ISO Standard Precise and Full-range Determination of Two-dimensional Equal Loudness Contours Fletcher-Munson is not Robinson-Dadson (PDF) Full Revision of International Standards for Equal-Loudness Level Contours (ISO 226) Test your hearing - A tool for measuring your equal-loudness contours Equal-loudness contour measurements in detail Evaluation of Loudness-level weightings and LLSEL JASA A Model of Loudness Applicable to Time-Varying Sounds AESJ Article v t e ISO standards by standard number List of ISO standards / ISO romanizations / IEC standards 1–9999 1 2 3 4 5 6 7 9 16 31 -0 -1 -2 -3 -4 -5 -6 -7 -8 -9 -10 -11 -12 -13 128 216 217 226 228 233 259 269 302 306 428 518 519 639 -1 -2 -3 -5 -6 646 690 732 764 843 898 965 1000 1004 1007 1073-1 1413 1538 1745 1989 2014 2015 2022 2047 2108 2145 2146 2240 2281 2709 2711 2788 2848 2852 3029 3103 3166 -1 -2 -3 3297 3307 3602 3864 3901 3977 4031 4157 4217 4909 5218 5428 5775 5776 5800 5964 6166 6344 6346 6385 6425 6429 6438 6523 6709 7001 7002 7098 7185 7200 7498 7736 7810 7811 7812 7813 7816 8000 8178 8217 8571 8583 8601 8632 8652 8691 8807 8820-5 8859 -1 -2 -3 -4 -5 -6 -7 -8 -8-I -9 -10 -11 -12 -13 -14 -15 -16 8879 9000/9001 9075 9126 9293 9241 9362 9407 9506 9529 9564 9594 9660 9897 9899 9945 9984 9985 9995 10000–19999 10005 10006 10007 10116 10118-3 10160 10161 10165 10179 10206 10218 10303 -11 -21 -22 -28 -238 10383 10487 10585 10589 10646 10664 10746 10861 10957 10962 10967 11073 11170 11179 11404 11544 11783 11784 11785 11801 11898 11940 (-2) 11941 11941 (TR) 11992 12006 12182 12207 12234-2 13211 -1 -2 13216 13250 13399 13406-2 13450 13485 13490 13567 13568 13584 13616 14000 14031 14224 14289 14396 14443 14496 -2 -3 -6 -10 -11 -12 -14 -17 -20 14644 14649 14651 14698 14750 14764 14882 14971 15022 15189 15288 15291 15292 15398 15408 15444 -3 15445 15438 15504 15511 15686 15693 15706 -2 15707 15897 15919 15924 15926 15926 WIP 15930 16023 16262 16612-2 16750 16949 (TS) 17024 17025 17100 17203 17369 17442 17799 18000 18004 18014 18245 18629 18916 19005 19011 19092 (-1 -2) 19114 19115 19125 19136 19439 19500 19501 19502 19503 19505 19506 19507 19508 19509 19510 19600:2014 19752 19757 19770 19775-1 19794-5 19831 20000+ 20000 20022 20121 20400 21000 21047 21500 21827:2002 22000 23270 23271 23360 24517 24613 24617 24707 25178 25964 26000 26300 26324 27000 series 27000 27001 27002 27006 27729 28000 29110 29148 29199-2 29500 30170 31000 32000 38500 40500 42010 55000 80000 -1 -2 -3 Category v t e Acoustics Engineering Architectural acoustics Monochord Reverberation Soundproofing String vibration string resonance Spectrogram Psychoacoustics Bark scale Combination tone Equal-loudness contour Fletcher–Munson curves Mel scale Missing fundamental Frequency and pitch Beat Formant Fundamental frequency Frequency spectrum harmonic spectrum Harmonic series inharmonicity Mersenne's laws Overtone Resonance Standing wave Node Subharmonic Acousticians John Backus Jens Blauert Ernst Chladni Hermann von Helmholtz Franz Melde Marin Mersenne Werner Meyer-Eppler Lord Rayleigh Joseph Sauveur D. Van Holliday Thomas Young Related topics Echo Infrasound Sound Ultrasound Musical acoustics piano violin Retrieved from "https://en.wikipedia.org/w/index.php?title=Equal-loudness_contour&oldid=816516870" Categories: PsychoacousticsAudio engineeringISO standardsHidden categories: Webarchive template wayback linksArticles needing additional references from October 2015All articles needing additional referencesAll articles with unsourced statementsArticles with unsourced statements from October 2008All articles with vague or ambiguous timeVague or ambiguous time from May 2015Pages using div col with deprecated parameters


Navigation menu Personal tools Not logged inTalkContributionsCreate accountLog in Namespaces ArticleTalk Variants Views ReadEditView history More Search Navigation Main pageContentsFeatured contentCurrent eventsRandom articleDonate to WikipediaWikipedia store Interaction HelpAbout WikipediaCommunity portalRecent changesContact page Tools What links hereRelated changesUpload fileSpecial pagesPermanent linkPage informationWikidata itemCite this page Print/export Create a bookDownload as PDFPrintable version Languages CatalàDeutschEspañolFrançaisGalegoItaliano日本語PolskiSlovenčinaSvenskaYorùbá Edit links This page was last edited on 21 December 2017, at 21:13. Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization. Privacy policy About Wikipedia Disclaimers Contact Wikipedia Developers Cookie statement Mobile view (window.RLQ=window.RLQ||[]).push(function(){mw.config.set({"wgPageParseReport":{"limitreport":{"cputime":"0.176","walltime":"0.253","ppvisitednodes":{"value":798,"limit":1000000},"ppgeneratednodes":{"value":0,"limit":1500000},"postexpandincludesize":{"value":56136,"limit":2097152},"templateargumentsize":{"value":1375,"limit":2097152},"expansiondepth":{"value":11,"limit":40},"expensivefunctioncount":{"value":3,"limit":500},"entityaccesscount":{"value":0,"limit":400},"timingprofile":["100.00% 156.725 1 -total"," 31.66% 49.620 1 Template:Unreferenced"," 22.90% 35.889 2 Template:Navbox"," 20.59% 32.262 1 Template:Ambox"," 18.57% 29.101 2 Template:Fix"," 17.85% 27.973 1 Template:ISO_standards"," 13.32% 20.883 1 Template:Citation_needed"," 10.02% 15.706 1 Template:Reflist"," 9.30% 14.568 2 Template:Delink"," 8.40% 13.168 1 Template:When"]},"scribunto":{"limitreport-timeusage":{"value":"0.054","limit":"10.000"},"limitreport-memusage":{"value":1965291,"limit":52428800}},"cachereport":{"origin":"mw1258","timestamp":"20180115213410","ttl":1900800,"transientcontent":false}}});});(window.RLQ=window.RLQ||[]).push(function(){mw.config.set({"wgBackendResponseTime":100,"wgHostname":"mw1269"});});


ISO_226 - Photos and All Basic Informations

ISO_226 More Links

EnlargeInternational Organization For StandardizationDecibelSound Pressure LevelFrequencyLoudnessPhonInternational Organization For StandardizationHumanHertzHuman EarKHzEar CanalTransfer FunctionOssiclesFletcher–Munson CurvesAbsolute Threshold Of HearingThreshold Of PainRobinson–Dadson CurvesISO 226International Organization For StandardizationHead ShadowPinna (anatomy)Head-related Transfer FunctionFletcher-Munson CurvesHeadphonesWikipedia:Citing SourcesWikipedia:VerifiabilityHelp:Introduction To Referencing With Wiki Markup/1Wikipedia:VerifiabilityHelp:Maintenance Template RemovalWikipedia:Citation NeededAnechoic ChamberWikipedia:Manual Of Style/Dates And NumbersTotal Harmonic DistortionA-weightingNoise MeasurementCritical BandDINAudio Quality MeasurementCompact CassetteDolbyBBC ResearchPink NoiseITU-R 468 Noise WeightingComité Consultatif International Pour La RadioInternational Electrotechnical CommissionBritish Standards InstitutionJapanese Industrial StandardsInternational Telecommunication UnionQuasi-peak DetectorAudiogramA-weightingCCIR (ITU) 468 Noise WeightingDB(A)Listener FatiguePure Tone AudiometrySound Level MeterLuminosity FunctionWayback MachineTemplate:ISO StandardsTemplate Talk:ISO StandardsInternational Organization For StandardizationList Of International Organization For Standardization StandardsList Of ISO RomanizationsList Of IEC StandardsISO 1ISO 2Preferred NumberISO 4ISO 5ISO 6ISO 7ISO 9A440 (pitch Standard)ISO 31ISO 31-0ISO 31-1ISO 31-2ISO 31-3ISO 31-4ISO 31-5ISO 31-6ISO 31-7ISO 31-8ISO 31-9ISO 31-10ISO 31-11ISO 31-12ISO 31-13ISO 128ISO 216ISO 217ISO 226British Standard Pipe ThreadISO 233ISO 259EnvelopeKappa NumberVicat Softening PointISO 428ISO 518ISO 519ISO 639ISO 639-1ISO 639-2ISO 639-3ISO 639-5ISO 639-6ISO/IEC 646ISO 690ISO 732Antimagnetic WatchISO 843ISO 898ISO 965ISO 1000Magnetic Ink Character Recognition135 FilmOCR-A FontISO 1413ALGOL 60ISO 1745ISO 1989ISO 2014ISO 2015ISO/IEC 2022ISO 2047International Standard Book NumberISO 2145ISO 2146ISO 2240Water Resistant MarkISO 2709ISO 2711ISO 2788ISO 2848ISO 2852126 FilmISO 3103ISO 3166ISO 3166-1ISO 3166-2ISO 3166-3International Standard Serial NumberISO 3307Kunrei-shiki RomanizationISO 3864International Standard Recording CodeISO 3977ISO 4031ISO 4157ISO 4217ISO/IEC 4909ISO/IEC 5218ISO 5428ISO 5775ISO 5776ISO 5800ISO 5964ISO 6166ISO 6344ISO 6346ISO 6385Water Resistant MarkANSI Escape CodeISO 6438ISO 6523ISO 6709ISO 7001ISO 7002PinyinPascal (programming Language)ISO 7200OSI ModelISO 7736ISO/IEC 7810ISO/IEC 7811ISO/IEC 7812ISO/IEC 7813ISO/IEC 7816ISO 8000ISO 8178Fuel OilFTAMISO 8583ISO 8601Computer Graphics MetafileISO/IEC 8652ISO 8691Language Of Temporal Ordering SpecificationISO/IEC 8820-5ISO/IEC 8859ISO/IEC 8859-1ISO/IEC 8859-2ISO/IEC 8859-3ISO/IEC 8859-4ISO/IEC 8859-5ISO/IEC 8859-6ISO/IEC 8859-7ISO/IEC 8859-8ISO-8859-8-IISO/IEC 8859-9ISO/IEC 8859-10ISO/IEC 8859-11ISO/IEC 8859-12ISO/IEC 8859-13ISO/IEC 8859-14ISO/IEC 8859-15ISO/IEC 8859-16Standard Generalized Markup LanguageISO 9000SQLISO/IEC 9126File Allocation TableISO 9241ISO 9362Shoe SizeManufacturing Message SpecificationISO 9529ISO 9564X.500ISO 9660ISO 9897C (programming Language)POSIXISO 9984ISO 9985ISO/IEC 9995ISO 10005ISO 10006ISO 10007ISO/IEC 10116Whirlpool (cryptography)ISO 10160ISO 10161Guidelines For The Definition Of Managed ObjectsDocument Style Semantics And Specification LanguageISO 10206ISO 10218ISO 10303EXPRESS (data Modeling Language)ISO 10303-21ISO 10303-22ISO 10303-28STEP-NCISO 10383ISO 10487ArmSCIIIS-ISUniversal Coded Character SetTorxRM-ODPMultibusInternational Standard Music NumberISO 10962ISO/IEC 10967ISO/IEEE 11073ISO 11170ISO/IEC 11179ISO/IEC 11404JBIGISO 11783ISO 11784 & 11785ISO 11784 & 11785ISO/IEC 11801ISO 11898ISO 11940ISO 11940-2ISO/TR 11941ISO/TR 11941ISO 11992ISO 12006ISO/IEC TR 12182ISO/IEC 12207Tag Image File Format / Electronic PhotographyPrologPrologPrologIsofixTopic MapsISO 13399ISO 13406-2110 FilmISO 13485ISO 13490ISO 13567Z NotationISO 13584International Bank Account NumberISO 14000ISO 14031ISO 14224PDF/UAHorsepowerISO/IEC 14443MPEG-4MPEG-4 Part 2MPEG-4 Part 3Delivery Multimedia Integration FrameworkH.264/MPEG-4 AVCMPEG-4 Part 11MPEG-4 Part 12MPEG-4 Part 14MPEG-4 Part 14MPEG-4 Part 14ISO 14644STEP-NCISO 14651ISO 14698ISO 14750Software MaintenanceC++ISO 14971ISO 15022ISO 15189ISO/IEC 15288Ada Semantic Interface SpecificationISO 15292ISO 15398Common CriteriaJPEG 2000Motion JPEG 2000HTMLPDF417ISO/IEC 15504International Standard Identifier For Libraries And Related OrganizationsISO 15686ISO/IEC 15693International Standard Audiovisual NumberISO 15706-2International Standard Musical Work CodeISO 15897ISO 15919ISO 15924ISO 15926ISO 15926 WIPPDF/XMaxiCodeECMAScriptPDF/VTISO 16750ISO/TS 16949ISO/IEC 17024ISO/IEC 17025ISO 17100:2015Open Virtualization FormatSDMXLegal Entity IdentifierISO/IEC 27002ISO/IEC 18000QR CodeISO/IEC 18014ISO 18245Process Specification LanguagePhotographic Activity TestPDF/AISO 19011ISO 19092-1ISO 19092-2ISO 19114ISO 19115Simple Feature AccessISO 19136ISO 19439Common Object Request Broker ArchitectureUnified Modeling LanguageMeta-Object FacilityXML Metadata InterchangeUnified Modeling LanguageKnowledge Discovery MetamodelObject Constraint LanguageMeta-Object FacilityXML Metadata InterchangeBusiness Process Model And NotationISO 19600:2014ISO/IEC 19752RELAX NGISO/IEC 19770X3DISO/IEC 19794-5Cloud Infrastructure Management InterfaceISO/IEC 20000ISO 20022ISO 20121ISO 20400MPEG-21International Standard Text CodeISO 21500ISO/IEC 21827ISO 22000C Sharp (programming Language)Common Language InfrastructureLinux Standard BasePDF/ELexical Markup FrameworkISO-TimeMLCommon LogicISO 25178ISO 25964ISO 26000OpenDocumentDigital Object IdentifierISO/IEC 27000-seriesISO/IEC 27000ISO/IEC 27001ISO/IEC 27002ISO/IEC 27006International Standard Name IdentifierISO 28000ISO 29110Requirements EngineeringJPEG XROffice Open XMLRuby (programming Language)ISO 31000Portable Document FormatISO/IEC 38500Web Content Accessibility GuidelinesISO/IEC 42010ISO 55000ISO/IEC 80000ISO 80000-1ISO 80000-2ISO 80000-3Category:ISO StandardsTemplate:AcousticsTemplate Talk:AcousticsAcousticsAcoustical EngineeringArchitectural AcousticsMonochordReverberationSoundproofingString VibrationString ResonanceSpectrogramPsychoacousticsBark ScaleCombination ToneFletcher–Munson CurvesMel ScaleMissing FundamentalFrequencyPitch (music)Beat (acoustics)FormantFundamental FrequencyFrequency SpectrumHarmonic SpectrumHarmonicHarmonic Series (music)InharmonicityMersenne's LawsOvertoneAcoustic ResonanceStanding WaveNode (physics)Undertone SeriesJohn Backus (acoustician)Jens BlauertErnst ChladniHermann Von HelmholtzFranz MeldeMarin MersenneWerner Meyer-EpplerJohn Strutt, 3rd Baron RayleighJoseph SauveurD. Van HollidayThomas Young (scientist)Echo (phenomenon)InfrasoundSoundUltrasoundMusical AcousticsPiano AcousticsBasic Physics Of The ViolinHelp:CategoryCategory:PsychoacousticsCategory:Audio EngineeringCategory:ISO StandardsCategory:Webarchive Template Wayback LinksCategory:Articles Needing Additional References From October 2015Category:All Articles Needing Additional ReferencesCategory:All Articles With Unsourced StatementsCategory:Articles With Unsourced Statements From October 2008Category:All Articles With Vague Or Ambiguous TimeCategory:Vague Or Ambiguous Time From May 2015Category:Pages Using Div Col With Deprecated ParametersDiscussion About Edits From This IP Address [n]A List Of Edits Made From This IP Address [y]View The Content Page [c]Discussion About The Content Page [t]Edit This Page [e]Visit The Main Page [z]Guides To Browsing WikipediaFeatured Content – The Best Of WikipediaFind Background Information On Current EventsLoad A Random Article [x]Guidance On How To Use And Edit WikipediaFind Out About WikipediaAbout The Project, What You Can Do, Where To Find ThingsA List Of Recent Changes In The Wiki [r]List Of All English Wikipedia Pages Containing Links To This Page [j]Recent Changes In Pages Linked From This Page [k]Upload Files [u]A List Of All Special Pages [q]Wikipedia:AboutWikipedia:General Disclaimer



view link view link view link view link view link