Brody, T., J. Flores, and and P. Mello. “A Closed Formula for the $3nj$ Coefficients of R$_3$”. Revista Mexicana De Física, vol. 17, no. 4, Jan. 1968, pp. 301-13, https://rmf.smf.mx/ojs/index.php/rmf/article/view/920.