GadomskiiL.Y., GrebenikovE.A., Gurskaya A.R. and ZemtsovaN.I. 1998. New classes of exact solutions for a problem of many bodies that attract one another according to an arbitrary law depending on the distances between bodies. Ukrains’kyi Matematychnyi Zhurnal. 50, 3 (Mar. 1998), 329–337.