Development of the Caffeine Withdrawal Symptom Questionnaire: Caffeine withdrawal symptoms cluster into 7 factors

Huntley, Edward; Juliano, Laura M; Harrell, Paul T; Westerman, Ashley T. (2012). Development of the Caffeine Withdrawal Symptom Questionnaire: Caffeine withdrawal symptoms cluster into 7 factors. Drug and alcohol dependence. 124(3), 229-234.