Historic.preservation Preserving old buildings is a psychological as well as economic resource says James Biddle in Denver visit. Post Mr 30 1977 p.18 Graduate level course in historic preservation offered at University of Colorado at Denver Dept. of Continuing Education. RMN Home Living S 17, 1977 p.13B, 17B Rae Sibley and Sandy Wherley of Aurora operate business, Nostalgia Bath, repairing and restoring bathtubs and sinks. AMN My 13 , 1978 p. 16B