PHAT, Tran Huu; LONG, Nguyen Van. On the loop expansion of the effective action. <b>Communications in Physics</b>, <i>[S. l.]</i>, v. 14, n. 2, p. 65–73, 2007. DOI: 10.15625/0868-3166/14/2/10696. Disponível em: https://vjs.ac.vn/cip/article/view/10696. Acesso em: 2 jan. 2026.