Akiskal, H. S., Bitar, A. H., Puzantian, V. R. et al.: The nosological status of neurotic depression: A prospective 3-4 year follow-up examination in the light of the primary-secondary and the unipolar-bipolar dichotomies. Arch. Gen. Psychiat., 35; 756-766, 1978.
Akiskal, H. S.: Dysthymic disorder: psychopathology of proposed chronic depressive subtypes. Am. J. Psychiatry, 140; 11-20, 1983.
Akiskal, H. S. and Mullya, G.: Criteria for “soft” bipolar spectrum: Treatment implications. Psychopathol. Bull., 23; 68-73, 1987.