ASERRAR, Youssef; ELQORACHI, Elhoucien. Cosine and sine addition and subtraction law with an automorphism. Annales Mathematicae Silesianae, [S. l.], v. 38, n. 2, p. 155–176, 2023. Disponível em: https://journals.us.edu.pl/index.php/AMSIL/article/view/16429. Acesso em: 5 dec. 2025.