Fu Jow Pai and Hung Gar

I may be wrong, but I've been reading that Fu Jow Pai is derived from the techniques of Hung Gar. Is this true and are there any significant differences that set these styles aside?



Are there other styles derived from Hung Gar?



Also while I am on the subject for comparative purposes, are there any books for reference on Fu Jow Pai (or other styles, such as leopard and dragon).