Gillen, T. (1997). Positive influencing skill. Jaico.
Chicago Style aipamenaGillen, Terry. Positive Influencing Skill. Bombay: Jaico, 1997.
MLA aipamenaGillen, Terry. Positive Influencing Skill. Jaico, 1997.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.