TY JOUR TI THE CONFESSIONAL HERITAGE OF THE PENZA REGION AS AN ECONOMIC POTENTIAL FOR TOURISM DEVELOPMENT: CLASSIFICATION, PROBLEMS, AND COMMERCIALIZATION MODELS KW confessional heritage KW religious tourism KW Penza Oblast KW economic potential KW tourism infrastructure KW commercialization models KW cultural heritage KW spiritual centers JO INTERNATIONAL AGRICULTURAL JOURNAL AU Malyshev, A.A. AU Ishamyatova, I.H. AU Solodkov, N.N. PY 2026 IS 9 PB Electronic science