1. Fluctuations in the abundance of species considered mathematically;Volterra;Nature,1926
2. Circular causal systems in ecology;Hutchinson;Ann. N.Y. Acad. Sci.,1948
3. Linear Differential Equations with Delayed Argument;Myshkis,1972
4. Delay Differential Equations with Applications in Population Dynamics;Kuang,1993
5. Mathematical Models in Population Biology and Epidemiology;Brauer,2001