K. Ananda, Y. H. Gangadharaiah and H. Nagarathnamma 2020. Combined impact of variable internal heat source and variable viscosity on the onset of convective motion in a porous layer. Malaya Journal of Matematik. 8, 03 (Jul. 2020), 973–976. DOI:https://doi.org/10.26637/MJM0803/0042.