¬ródło: | W: 15th International Multidisciplinary Scientific GeoConference SGEM 2015. Ecology, economics, education and legislation, 18-24, June, 2015, Albena, Bulgaria. Conference proceedings. Vol. 3, Environmental economics, education & accreditation in geosciences. Sofia : STEF92 Technology, 2015, s. 697-704, bibliogr. 15 poz. |