Geograf (geografia ekonomiczna).

Migration processses in small European regions during transition period / ed. by Krystian Heffner, Jernej Zupančič. - Opole, 2000. (Instytut Geografii, Ljubljana)

Small regions in United Europe / ed. by Krystian Heffner, Vladimir Klemenčič. - Opole, 1995. Biogram ; (University of Ljubljana, Slovenia)

Oxford-online