Cole, A. A., ., and A. F. Sarmiento G. “The Gravitational Frequency Shift for a Class of Non-Metric Theories of Gravity”. Revista Mexicana De Física, vol. 31, no. 2, Jan. 1984, pp. 385-99, https://rmf.smf.mx/ojs/index.php/rmf/article/view/1323.