Foundations of Computer Science
Aho, Alfred and Ullman, Jeffrey,
Computer Science Press,
W.H. Freeman and Company New York, 1992.
Learning Perl, Second Edition
Randal L. Schwartz and Tom Christiansen,
O'Reilly & Associates, Inc., Sebastpool, CA (1997).
The exercises and some example scripts
from this book are available through FTP.
Programming Perl, Second Edition
Larry Wall, Tom Christiansen and Randal L. Schwartz,
O'Reilly & Associates, Inc., Sebastpool, CA (1996).
Official Guide to Programming with CGI.pm
Lincoln Stein,
John Wiley & Sons, Inc. (1998).