Ringstad, Arnold (2) Hoppmann, Jürgen G. H. (2) Lobel, Arnold (2) Brzozowska, Anna (czestochowa University Of Technology, Brzezinski, Stanislaw (akademia Ekonomiczno-humanistyczna, Pabian, Arnold (czestochowa University Of Technology), Pabian, Barbara (university Of Economic In Katowice (1) Horner, Arnold (1)