Outstanding scenic geological features of Pennsylvania / Alan R. Geyer [and] William H. Bolles.Alan R. Geyer · First published 1979Open the Tome
Environmental geology of the greater Harrisburg metropolitan area / William G. McGlade, Alan R. Geyer.William G. McGlade · First published 1976Open the Tome
Environmental geology for land-use planning / Alan R. Geyer, William G. McGlade.Alan R. Geyer · First published 1972Open the Tome
Geology, mineral resources, and environmental geology of the Palmyra Quadrangle, Lebanon and Dauphin Counties, by Alan R. GeyerAlan R. Geyer · First published 1970Open the Tome
Die Mukâtarah von at-Tayâlisi, hrsg. von R. GeyerMuhammad ibn Ja'far Tayalisi · First published 1927Open the Tome
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