M. KEJNA, J. USCKA-KOWALKOWSKA, A. ARAŹNY, M. KUNZ, R. MASZEWSKI, and R. PRZYBYLAK, “SPATIAL DIFFERENTIATION OF GLOBAL SOLAR RADIATION IN TORUŃ AND ITS SUBURBAN AREA (CENTRAL POLAND) IN 2012”, BOGPGS, no. 7, pp. 27–56, Mar. 2015.