The following are APA sample citations from three commonly used types of sources: books, journal articles, and dissertations.
Book:
Striegel-Moore, R., & Smolak, L. (2001). Eating Disorders: Innovative Directions in Research and Practice. Washington, DC: American Psychological Association.
Journal Article:
Ferguson, C.J., Muñoz, M.E., Garza, A., & Galindo, M. (2014). Concurrent and Prospective Analyses of Peer, Television and Social Media Influences on Body Dissatisfaction, Eating Disorder Symptoms and Life Satisfaction in Adolescent Girls. Journal of Youth and Adolescence: A Multidisciplinary Research Publication 43(1), 1-14.
Dissertation:
Anderson, J.M. (2013). Gender Differences in the Attribution of Stigma to Individuals with Anorexia Nervosa: A Grounded Theory Exploration (Doctoral Dissertation). Retrieved from ProQuest Dissertations and Theses Global. Order No. 3593356.