LI, Y.; ZHAO, K. Eight positive periodic solutions to three species non-autonomous Lotka-Volterra cooperative systems with harvesting terms. Topological Methods in Nonlinear Analysis, [S. l.], v. 37, n. 2, p. 225–234, 2011. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.2011.012. Acesso em: 5 lip. 2024.