I. N. KHAIRULLAEV. BIERMAN-SCHWINGER PRINCIPLE FOR A SINGLE MODEL PARTIAL-INTEGRAL OPERATOR. European Journal of Humanities and Educational Advancements, [S. l.], v. 2, n. 12, p. 132-135, 2021. Disponível em: https://scholarzest.com/index.php/ejhea/article/view/1658. Acesso em: 10 jan. 2025.