TY - RPRT TI - Map of land modified by man in part of the Monongahela 7 1/2-minute Quadrangle, Allegheny County and vicinity, Pennsylvania AU - W.E. Davies PY - 1974 DO - 10.3133/ofr74293 UR - https://pubs.usgs.gov/publication/ofr74293 ID - ofr74293 ER -