1. Ahmad, I., Mukhtar, A.: Stochastic approach for the solution of multi-pantograph differential equation arising in cell-growth model. Appl. Math. Comput. 261, 360–372 (2015)
2. Alsuyuti, M., Doha, E., Ezz-Eldien, S., Bayoumi, B., Baleanu, D.: Modified Galerkin algorithm for solving multi type fractional differential equations. Math. Appl. Sci. 42, 1389–1412 (2019)
3. Baker, C.T.: Retarded differential equations. J. Comput. Appl. Math. 125(1–2), 309–335 (2000)
4. Balachandran, K., Kiruthika, S., Trujillo, J.: Existence of solutions of nonlinear fractional pantograph equations. Acta Math. Sci. 33(3), 712–720 (2013)
5. Bellen, A., Zennaro, M.: Numerical Methods for Delay Differential Equations. Oxford University Press, Oxford (2013)