On the Dynamics of a Viral Marketing Model with Optimal Control using Indirect and Direct Methods. Statistics, Optimization & Information Computing, [S. l.], v. 6, n. 4, p. 633–644, 2018. DOI: 10.19139/soic.v6i4.441. Disponível em: https://www.iapress.org/index.php/soic/article/view/soic20181212. Acesso em: 23 apr. 2026.