Radhakrishnamacharya, G., and R. Sharma. “Motion of a Self-Propelling Micro-Organism in a Channel Under Peristalsis: Effects of Viscosity Variation”. Nonlinear Analysis: Modelling and Control, vol. 12, no. 3, July 2007, pp. 409-18, https://doi.org/10.15388/NA.2007.12.3.14703.