%0 Journal Article %A L. A. Khalfin %T Induced singularities in the mass distribution of unstable particles associated with cascade decay and the problem of $CP$ invariance %J Teoretičeskaâ i matematičeskaâ fizika %D 1975 %P 260-264 %V 25 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/item/TMF_1975_25_2_a9/ %G ru %F TMF_1975_25_2_a9