Nikishov A.I. ,     Pichkurov N.V. Direct e~+e~- pair production by muons. Pr. FIAH , N100 , с. 19 p. , 01.1975   Nikishov A.I. ,     Pichkurov N.V. Energy spectrum of e~+e~- pair created in muon colision with atom. Pr. FIAH , N69 , с. 27 p. , 01.1980