P.K. · Paul K · Paul Knorr · Paul O.
| title | ISBN-13 | year of publica- tion | other author(s) |
|---|---|---|---|
| Experts: A Comprehensive D20 Sourcebook for Fantasy Role-Playing Games | 978-0-9722511-0-5 | 2002 | Michael J. Varhola |
| Experts v.3.5: A Comprehensive OGL Sourcebook For Fantasy Role-Playing Games | 978-0-9722511-9-8 | 2005 | Michael J. Varhola · Perry Frix · Skirmisher Game Development Group · Gary Gygax |
| Tests of Skill: A d20 Adventure and Sourcebook for Fantasy Role-Playing Games | 978-0-9722511-2-9 | 2004 | Michael J. Varhola · Skirmisher Game Development Group |
| Warriors: A Comprehensive D20 Sourcebook for Fantasy Role-Playing Games | 978-0-9722511-1-2 | 2003 | Michael J. Varhola · Sharon Daugherty · David L. Thomas · Luke Gygax |