References
- Aftabizadeh , A. R. and Leela , S. R. 1984 . Proc. of Colloquia on Qualitative Theory of Differential Equations at Bolyai Institute , Hungary : Szeged .
- Shouchuan Hu , V. Lakshmikantham . Periodic boundary value problems for integro-differential equations of Volterra type , to appear .
- Laade , G. S. , Lakshmikantham , V. and Vatsala , A. S. 1985 . Monotone Iterative Techniques for Nonlinear Differential Equations , Pitman Publishing, Inc .