00496naa#a2200169#i#450# EN\NORMA\bibl\6190 20250112123645.7 1605-6590 20150625b2015####ek#y0engy0150####ca RUS RU Contract System: Main Problems of Law Enforcement and Ways of their Overcoming Journal article Moscow Legal publishing house Norm 2015 0 с. Journal article local Byelyayeva Olga naukaru.ru