MONADIC DESCRIPTION OF SYSTEMS OF RECORDING AND MAXWELL EQUATIONS СтатьяMITSKEVICH N.V., KALEV D.A.DOKLADI NA BOLGARSKATA AKADEMIYA NA NAUKITE. Том 28. 1975. С. 735-738
PERIODIC-SOLUTIONS TO LINEAR-SYSTEMS WITH SMALL PARAMETER BY DERIVATIVE СтатьяROZHKOV V.I.Doklady Akademii nauk SSSR. Том 224. 1975. С. 1268-1271