Agarwal R.P., O'Regan D., Wong Patricia J.Y. Positive Solutions of Differential, Difference and Integral Equations

Springer, 2010. — 425 p. — ISBN: 9048151538.In analysing nonlinear phenomena many mathematical models give rise to problems for which only nonnegative solutions make sense. In the last few years this discipline has grown dramatically. This state-of-the-art volume offers the authors' recent work, reflecting some of the major advances in the field as well as the diversity of the subject.