Alexander GE e Crutcher MD, Preparation for movement: neural representations of intended direction in three motor areas of the monkey, in Journal of Neurophysiology, vol. 64, n. 1, luglio 1990, pp. 133–50, PMID2388061.
Delong MR, Georgopoulos AP, Crutcher MD, Mitchell SJ, Richardson RT e Alexander GE, Functional organization of the basal ganglia: contributions of single-cell recording studies, in Ciba Found Symp., vol. 107, 1984, pp. 64–82, PMID6389041.