1. Mayer, K.H., Ayotte, D., Groopman, J.E., Stoddard, A.M., Sarngadharan, M. and Gallo, R., Am. J. Med., 80 (1987) 357.
2. Smith, P.D. and Mai, U.E.H., Gastroenterol. Clin. North Am., 21 (1992) 331.
3. Amerongen, H.M., Weltzin, R., Farner, C.M., Michetti, P., Haseltine, W.A. and Neutra, M.R., J. Acquired Immune Defic. Syndr., 4 (1991) 760.
4. Tucker, S.P. and Compans, R.W., Adv. Virus Res., 42 (1993) 187.
5. Levy, J.A., Margaretten, W. and Nelson, J., Am. J. Gastroenterol., 84 (1989) 787.