Volker W. THÜREY. Study on the Complex Angle in Normed Spaces. Newest Updates in Physical Science Research Vol. 9, [S. l.], p. 74–79, 2021. DOI: 10.9734/bpi/nupsr/v9/9802D. Disponível em: https://stm.bookpi.org/NUPSR-V9/article/view/1938. Acesso em: 13 jun. 2026.