S. INDRAKALA. A study on mathematical methods for predicting accuracy of crude oil futures prices by multi grey Markov model. Malaya Journal of Matematik, India, v. 9, n. 01, p. 621–626, 2021. Disponível em: https://www.malayajournal.org/index.php/mjm/article/view/1095. Acesso em: 16 jul. 2024.