American Birding Association Field Guide to Birds of WisconsinCharles Hagner, Brian Small · First published 2019Open the Tome
Early History of the Falls of Schuylkill, ManayunkCharles V. Hagner · First published 2018Open the Tome
Early History of the Falls of Schuylkill, Manayunk, Schuylkill and Lehigh Navigation Companies, Fairmount Waterworks, EtcCharles Valerius Hagner · First published 1869 · Latest edition 2018Open the Tome
