Elena Petrova, Larisa Linkina (2017). BOUNDARIES AND STRUCTURE OF AKCHAGYLIAN STAGE WITHIN MIDDLE VOLGA AREA. SGEM International Multidisciplinary Scientific GeoConference EXPO Proceedings; 17th International Multidisciplinary Scientific GeoConference SGEM2017, Science and Technologies in Geology, Exploration and Mining, 65-72. https://doi.org/10.5593/sgem2017/11/s01.008