Omondi EO, Orwa TO, Nyabadza F
Mathematical Biosciences
(2018)
https://doi.org/10.1016/j.mbs.2017.11.009
Omondi EO, Nyabadza F, Smith RJ
Cogent Mathematics & Statistics
https://doi.org/10.1080/23311835.2018.1429700