Authors: NIKOLOV T TCHOUMATCHENCO P

Citation: T. Nikolov et P. Tchoumatchenco, NEW DATA ABOUT THE LOWER BOUNDARY OF THE URGON GROUP OF VRACA IN THE ISKAR GORGE (FORE-BALKAN), Dokladi na B"lgarskata akademia na naukite, 45(8), 1992, pp. 75-77