1. A comparison principle for terminal value problems in ordinary differential equations;Hallam;Trans. Am. math. Soc.,1972
2. One-sided estimates on the conditions for existence and uniqueness of solutions of the limit Cauchy problem in a Banach space;Mamedov;Sibirsk, Mat. Ž.,1965
3. Solutions of Hallam's problem on the terminal comparison principle for ordinary differential inequalities;Vidossich;Trans. Am. math. Soc.,1976