Martínez-y-Romero, R., and Macbeth Baruch Rangel Orduña. “Critical Strings and Analyticity of the $\zeta$ Function Analyticity”. Revista Mexicana De Física E, vol. 56, no. 1 Jan-Jun, Jan. 2010, pp. 75-82, https://rmf.smf.mx/ojs/index.php/rmf-e/article/view/4627.