BLAŽIĆ, N.; VUKMIROVIĆ, S. Examples of self-dual, Einstein metrics of $(2,2)$-signature. MATHEMATICA SCANDINAVICA, [S. l.], v. 94, n. 1, p. 63–74, 2004. DOI: 10.7146/math.scand.a-14430. Disponível em: https://www.mscand.dk/article/view/14430. Acesso em: 5 may. 2024.