Cunningham J
Z Naturforsch C Biosci. 1979 Aug;34(7-8):647-8. doi: 10.1515/znc-1979-7-829.
A deterministic model of recurrent epidemics is constructed using a non linear relationship between infection rate and number of contacts. Epidemic waves which are not damped are predicted and a relationship between community size and the period of recurrence is established. A possible explanation of measles outbreaks is suggested.