ELST, A. F. M. Ter; PRADO, Humberto. Gaussian bounds for reduced heat kernels of subelliptic operators on nilpotent Lie groups. Mathematica Scandinavica, Berkeley, CA, United States, v. 90, n. 2, p. 251–266, 2002. DOI: 10.7146/math.scand.a-14373. Disponível em: https://journals.msp.org/mscand/article/view/846. Acesso em: 24 jul. 2026.