AUTONOMY IN THE RUSSIAN FEDERATION: THEORY AND PRACTICE СтатьяKartashkin V.A., Abashidze A.Kh.International Journal on Minority and Group Rights. Том 10. 2003. С. 203-220
ON THE STRUCTURE OF VARIATIONAL EQUATIONS WITH THE SYMMETRICAL OPERATOR D DT СтатьяSAVCHIN V.M.Differential Equations. Том 29. 1993. С. 1532-1537