Cambiaggio, M., A. Plastino, L. Szybisz, and and M. de Llano. “Hartree-Fock Theory in Exactly Soluble Models With a Finite Number of Particles”. Revista Mexicana De Física, vol. 27, no. 2, Jan. 1980, pp. 223-41, https://rmf.smf.mx/ojs/index.php/rmf/article/view/1163.