Yang Enhao, Existence and Uniqueness of Positive Solutions to Sublinear-Linear Initial Value Problems, Acta Mathematica Sinica, New Series Chinese Journal of Mathematics, 10(1), 1994, pp. 19-29
Existence and uniqueness conditions for nonnegative solutions to initial value prob- lems of general sublinear-linear differential equations are obtained. They extend the uniqueness theorem due to H.Murakami and the main results of H.G. Kaper and M.K.Kwong.