Die brücke der Pennsylvania=eisenbahn über den Delaware bei Philadelphia, erbaut von den Pencoyd Iron Works, A. + P. Roberts CompanyF. C. Kunz · First published 1901Open the Tome
Ore deposit models. Edited by R.G. Roberts and P.A. SheahanPatricia Sheahan, Roberts, R. G. · First published 1988Open the Tome
