Formation and development of clusters in the Russian regional agro-industrial complex Anatoly Sharnin, Olga Frolova, Guzaliya Klychova, Nuriya Nigmatullina and Albert Iskhakov E3S Web Conf., 91 (2019) 06005 Published online: 02 April 2019 DOI: 10.1051/e3sconf/20199106005