Skrypnik, W. I. “On Lattice Oscillator-Type Kirkwood - Salsburg Equation With Attractive Manybody Potentials”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 62, no. 12, Dec. 2010, pp. 1687–1704, https://umj.imath.kiev.ua/index.php/umj/article/view/2992.