Ziyi Sun, Hua Su
      Positive solutions of impulsive differential equations
      Applied Mathematical Sciences, Vol. 11, 2017, no. 43, 2141-2149
      https://doi.org/10.12988/ams.2017.77234
Copyright © 2017 Ziyi Sun and Hua Su. This article is distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.