KALMBACH H.E., G. Projective Gravity. International Journal of Contemporary Research and Review, [S. l.], v. 9, n. 03, p. 20181–20183, 2018. DOI: 10.15520/ijcrr/2018/9/03/466. Disponível em: http://ijcrr.info/index.php/ijcrr/article/view/466. Acesso em: 7 may. 2024.