7.Vowel
... unrounded, front rounded, and back rounded vowels, plus an opencentralvowel: ... Retrieved from " http://en.wikipedia.org/wiki/Vowel" ...
-- http://schools-wikipedia.org/wp/v/Vowel.htm
9.yawiki.org entry for Vowel
Interesting article about Vowel by yet another wiki - The Free Java Powered ... unrounded, front rounded, and back rounded vowels, plus an opencentralvowel: ...
-- http://yawiki.org/proc/Vowel