Ardjouni, A., and A. Djoudi. “EXISTENCE, UNIQUENESS AND POSITIVITY OF SOLUTIONS FOR A NEUTRAL NONLINEAR PERIODIC DYNAMIC EQUATION ON A TIME SCALE”. Journal of Nonlinear Analysis and Optimization: Theory & Applications (JNAO), vol. 6, no. 2, Dec. 2016, pp. 19-29, https://ph03.tci-thaijo.org/index.php/jnao/article/view/2777.