Hi, Andrés - does your book have any Bixio songs at all? I've found the same thing with some U.S. songwriters - their songs just aren't found in songbooks very ofter. Irving Berlin is a good example. He was one of the most prolific of the "great" U.S. songwriters of the last century, but his publisher seems to guard his works closely and they only rarely appear in songbooks and fakebooks.
-Joe Offer-