This is an archive of past FreeBSD releases; it's part of the FreeBSD Documentation Archive.
Asente, Paul. X Window System Toolkit. Digital Press. ISBN 1-55558-051-3
Computer Systems Research Group, UC Berkeley. 4.4BSD Programmer's Reference Manual. O'Reilly & Associates, Inc., 1994. ISBN 1-56592-078-3
Computer Systems Research Group, UC Berkeley. 4.4BSD Programmer's Supplementary Documents. O'Reilly & Associates, Inc., 1994. ISBN 1-56592-079-1
Harbison, Samuel P. and Steele, Guy L. Jr. C: A Reference Manual. 4rd ed. Prentice Hall, 1995. ISBN 0-13-326224-3
Kernighan, Brian and Dennis M. Ritchie. The C Programming Language.. PTR Prentice Hall, 1988. ISBN 0-13-110362-9
Lehey, Greg. Porting UNIX Software. O'Reilly & Associates, Inc., 1995. ISBN 1-56592-126-7
Plauger, P. J. The Standard C Library. Prentice Hall, 1992. ISBN 0-13-131509-9
Stevens, W. Richard. Advanced Programming in the UNIX Environment. Reading, Mass. : Addison-Wesley, 1992 ISBN 0-201-56317-7
Stevens, W. Richard. UNIX Network Programming. 2nd Ed, PTR Prentice Hall, 1998. ISBN 0-13-490012-X
Wells, Bill. ``Writing Serial Drivers for UNIX''. Dr. Dobb's Journal. 19(15), December 1994. pp68-71, 97-99.