1. Amsel A & Work M S (1961). The role of learned factors in spontaneous activity. Journal of Comparative and Physiological Psychology, 54, 527–532.
2. Andersen P & Andersson S A (1968). Physiological Basis of the Alpha Rhythm, New York: Appleton-Centry-Crofts.
3. Anisman H (1978). Neurochemical changes elicited by stress. Behavioural correlates. In H Anisman & G Bignami (Eds), Psychopharmachology of Aversively Motivated Behaviour. New York: Plenum.
4. Atkinson J W & Feather N T (1966). A Theory of Achievement Motivation, New York: Wiley.
5. Bakke H K, Murison R & Walther B (1985). Effort of central noradrenaline depletion on corticosterone levels and gastric ulcerations in rat. Brain Research, In press.