Moreira de Oliveira, C. and Romero, O.J. 2021. Approximate calculation model and Gibbs model to determine operating parameters of the sucker-rod pumping system. Latin American Journal of Energy Research. 8, 1 (Jul. 2021), 67–85. DOI:https://doi.org/10.21712/lajer.2021.v8.n1.p67-85.