Cattell's 16 PF Trait Theory
Here's your citation in American Psychological Association (APA) format:
Cattell's 16 PF Trait Theory. (n.d.). In Alleydog.com's online glossary. Retrieved from: https://www.alleydog.com/glossary/definition-cit.php?term=Cattell%27s+16+PF+Trait+Theory