On mathematical modelling of optimal control of typhoid fever with efficiency analysis. Journal of the Nigerian Society of Physical Sciences, [S. l.], v. 6, n. 4, p. 2057, 2024. DOI: 10.46481/jnsps.2024.2057. Disponível em: https://journal.nsps.org.ng/index.php/jnsps/article/view/2057.. Acesso em: 16 oct. 2024.