Siudek, T., and M. Vashchyk. “ECONOMIC DEVELOPMENT OF RURAL AREAS IN EUROPEAN UNION MEMBER STATES IN 2000-2012”. Acta Scientiarum Polonorum. Oeconomia, vol. 13, no. 3, Sept. 2014, pp. 95-104, https://aspe.sggw.edu.pl/article/view/487.