e/Phonological history of English high back vowels

Information
has gloss	eng: Most dialects of modern English have two high back vowels: the close back rounded vowel found in words like goose, and the near-close near-back rounded vowel found in words like foot. This article discusses the history of these vowels in various dialects of English, focusing in particular on phonemic splits and mergers involving these sounds.
lexicalization	eng: Phonological history of English high back vowels
instance of	c/Splits and mergers in English phonology