X Window System : core library and standards : X version 11, releases 6 and 6.1
Robert W. Scheifler, James Gettys, Al Mento, Donna Converse · Digital Press eBooks · 1996
Xlib - C language interface inter-client communication conventions manual X logical font description. Appendices: Xlib functions and protocol requests X font cursors extensions compatibility functions bitmap distribution format compound text encoding X consortium character set names.