1. Anderson, R.M., May, R.M.: Infectious diseases of humans: dynamics and control. Oxford: Oxford University Press, 1991
2. Andreasen, V., Levin, S.A., Lin, J.: Z. Angew. Math. Mech. 52 (76), 421 (1996)
3. Andreasen, V., Lin, J., Levin, S.A.: J. Math. Biol. 35 (7), 825 (1997)
4. Callen, H.B. Thermodynamics and an introduction to thermostatistics. Wiley Text Books, second edition, 1985
5. Castillo-Chavez, C., Hethcote, H.W., Andreasen, V., Levin, S.A., Liu, M.W.: J. Math. Biol. 27, 233 (1985)