Aquino, Cícero P., Halyson I. Baltazar, and Henrique F. de Lima. “New Characterizations of Spacelike Hyperplanes in the Steady State Space”. Mathematica Scandinavica 126, no. 1 (March 29, 2020): 61–72. Accessed July 24, 2026. https://journals.msp.org/mscand/article/view/203.