LEERAWAT, U. Integration in Finite Terms which Includes Exponential Integral. Agriculture and Natural Resources, Bangkok, Thailand, v. 31, n. 4, p. 488–496, 1997. Disponível em: https://li01.tci-thaijo.org/index.php/anres/article/view/241005. Acesso em: 17 sep. 2026.