1. O. Arino -T. A. Burton -J. Haddock,Periodic solutions of functional differential equations, Roy. Soc. Edinburgh, Proc. A,101 (1985), pp. 253–271.
2. T. A. Burton,Periodicity and limiting equations in Volterra systems, Boll. Un. Mat. Ital., IV (1985), pp. 31–39.
3. T. A. Burton,Periodic solutions of linear Volterra equations, Funkcial. Ekvac.,27 (1984), pp. 229–253.
4. T. A. Burton,Periodic solutions of nonlinear Volterra equations. Funkcial. Ekvac.,27 (1985), pp. 301–317.
5. T. A. Burton,Periodic solutions of integrodifferential equations, J. London Math. Soc.,31 (1985), pp. 527–548.