A few African antelope pictures sought for a new book

I’ve been contacted by a South African, Willem Frost, who is finalising the manuscript for a book on the Antelopes of Africa. “The purpose is to draw attention to the plight of Africa’s antelopes, the numbers of which are on the decline almost everywhere.”

He needs a few more images to illustrate the book.:

He needs images of:
Ogylby’s duiker – Cephalophus ogylbyi
White-legged duiker – Cephalophus ogilbyi crusalbum
Brooke’s duiker – Cephalophus brookei
Gabon duiker (also known as white-bellied duiker) – Cephalophus leucogaster
Kafue lechwe – Kobus leche kafuensis

Can anyone help? Willem says that it goes without saying that you will retain copyright and will get credit for each photo used in the book.

thanks!

Jon