1
Graziano, Anthony M.
HarperCollins College Publishers,
1993,
3
Greaves, Richard L.
HarperCollinsCollegePublishers,
1993,
4
Sanderson, Stephen K.
HarperCollins College Publishers,
1995,
6
Riggio, Ronald E.
HarperCollinsCollegePublishers,
1996,