The following provide more information:
OpenMP API User’s Guide
Techniques for Optimizing Applications: High Performance Computing, by Rajat Garg and Ilya Sharapov, Sun Microsystems Press Blueprint, 2001.
High Performance Computing, by Kevin Dowd and Charles Severance, O’Reilly and Associates, 2nd Edition, 1998.
Parallel Programming in OpenMP, by Rohit Chandra et al., Morgan Kaufmann Publishers, 2001.
Parallel Programming, by Barry Wilkinson, Prentice Hall, 1999.