1. BARBER, H.R.K. (1977): Inmunobiology for the Clinician. John Wiley and. sons, New York.
2. CLARK, D.G.C., BARNETT., BRUNSCH-WIG, A. and HELLMAN, L. (1960): Cáncer, 13, 755.
3. COLLINS, C.G., ROMAN LOPEZ, J.S. and LEE, F.Y.L. (1970): Amer. J. Obst. Gyn. 108, 1187.
4. COLLINS, C.G., COLLINS, J.H., BARCLAY, D.L. and NELSON, E.W. (1968): Amer., Obstetrics & Gynecology, 87/6, 762.
5. DEAN, R.E., TAYLOR, E.S., WEISBROD, D.M, et al. (1974): Amer. J. Obstetrics & Gynecology, 119, 59.