Reference resources are a good place to start your research, because they help you to learn about an unfamiliar topic, narrow your topic by presenting specific issues within broader subject areas, identify keywords describing your topic, and identify important names and dates relating to your topic that help you to search other sources more efficiently.
Dictionaries
Dictionary of the Sport and Exercise Sciences (Print)
Dorland's Illustrated Medical Dictionary (Print)
Encyclopedias
Encyclopedia of Sports Science (Print)
Encyclopedia of Sports Medicine (Online)
Encyclopedia of Applied Psychology (Online)
Encyclopedia of Sports and Athletics (Print)
Encyclopedia of Mental Health (Print)
Gale Encyclopedia of Medicine (Print and Online)
MIT Encyclopedia of the Cognitive Sciences (Print)
Other Sources
Mental Measurements Yearbook (Print)
Sports: A Reference Guide and Critical Commentary (Print)
Health Sciences & Psychology Databases