LEDINGHAM, George F. In Memoriam: Robert David Symons, 1898-1973. Blue Jay, [S. l.], v. 31, n. 3, 1970. DOI: 10.29173/bluejay4152. Disponível em: https://bluejayjournal.ca/index.php/bluejay/article/view/4152. Acesso em: 16 apr. 2025.