V. Appala Raju, V. Sri Harsha, N. Bhanu Deepthi, and N. Prasanth, “Zonal stable election protocol for heterogeneous wireless sensor networks”, IJET, vol. 7, no. 2.7, pp. 725–728, Mar. 2018, doi: 10.14419/ijet.v7i2.7.10932.