On the previous forum there was a member called "heremæcg" (I believe?) who was interested in Yola and ran a wiki dedicated to it
Really the only other source on Yola that I am aware of (other than Wikipedia) is a book called, rather exhaustively, A Glossary, With Some Pieces Of Verse, Of The Old Dialect Of The English Colony In The Baronies Of Forth And Bargy, County of Wexford, Ireland (1867)
by Jacob Poole (the man responsible for compiling our knowledge of Yola). It's a very interesting read, with a wide variety of texts in Yola (and various related dialects), as well as a description of grammar and pronunciation.