ANDIMA, Susan; PAJOOHESH, Homeira; WILSON, Richard. Ralph David Kopperman, 1942-2021. Topology Proceedings, [S. l.], v. 61, p. i–xi, 2022. Disponível em: https://www.topologyproceedings.org/index.php/tp/article/view/79. Acesso em: 30 jun. 2026.