VÄÄNÄNEN, Keijo. Irrationality Measures of Numbers Related to Some $q$-Basic Hypergeometric Series. Mathematica Scandinavica, Berkeley, CA, United States, v. 114, n. 2, p. 254–263, 2014. DOI: 10.7146/math.scand.a-17110. Disponível em: https://journals.msp.org/mscand/article/view/422. Acesso em: 24 jul. 2026.