KULLI, V. R.; NIRANJAN, K. M. On Minimally Nonouterplanarity of the Semi Total (Point) Graph of a Graph. Journal of Scientific Research, [S. l.], v. 1, n. 3, p. 551–557, 2009. DOI: 10.3329/jsr.v1i3.2578. Disponível em: https://banglajol.info/index.php/JSR/article/view/2578. Acesso em: 20 may. 2022.