Plasma neurotransmitters, blood pressure and heart rate during supine resting, orthostasis and moderate exercise in severely ill patients: a model of failing to cope with stress. - Lechin,F.; van der Dijs,B.; Orozco,B.; Lechin,A.E.; Beaz,S.; Lechin,M.E.; Benaim,M.; Acosta,E.; Arocha,L.; Jimenez,V.; Leon,G.; Garcia,Z. (Psychother Psychosom, 1996)