Associative forms of the Russian Federation subjects' cooperation: constitutional legal research: abstract thesis for a scientific degree Candidate (Philosophy Doctor) of Legal Sciences: specialization 12.00.02 - the constitutional right; constitutional litigation; municipal law - Ibragimov A. G. (Arthur Hassanguseinovich) (Associative forms of the Russian Federation subjects' cooperation: constitutional legal research: abstract thesis for a scientific degree Candidate (Philosophy Doctor) of Legal Sciences: specialization 12.00.02 - the constitutional right; constitutional litigation; municipal law, 2020)