00575nam a2200205Ia 4500 CTU_86742 210402s9999 xx 000 0 und d 629.13 T831 Trimble, William F. High frontier : a history of aeronautics in Pennsylvania William F. Trimble Pittsburgh, Pa. University of Pittsburgh Press 1982 Aeronautics pennsylvania History Năm Trung tâm Học liệu Trường Đại học Cần Thơ