I m sorry I was lazy Here s where I got the information about the diphthongal variants of and they make it clear in the references that Wells 1982a is Wells J C Accents of English 1 An Introduction Cambridge Cambridge University Press They also say Cruttenden 2001 is Cruttenden A 2001 Gimson s Pronunciation of English 6th edn London Arnold A Handbook of Varieties of English Bernd Kortmann Edgar W Schneider Walter de Gruyter 2004 is where I got the information about monophthongization in Cockney they in turn referenced Wells 1982 In this case Wells 1982 309 refers to Wells J C Accents of English 2 The British Isles Cambridge Cambridge University Press There you go