RESSEL, P.; RICKER, W. J. Vector-valued positive definite functions, the Berg-Maserick theorem, and applications. Mathematica Scandinavica, Berkeley, CA, United States, v. 90, n. 2, p. 289–319, 2002. DOI: 10.7146/math.scand.a-14375. Disponível em: https://journals.msp.org/mscand/article/view/844. Acesso em: 24 jul. 2026.