JAWORSKI, Piotr. Witt rings of fields of formal power series in two variables. Annales Mathematicae Silesianae, [S. l.], v. 2, p. 13–29, 1986. Disponível em: https://journals.us.edu.pl/index.php/AMSIL/article/view/14314. Acesso em: 25 jun. 2025.