ArchitectFrederick J. OsterlingAmerican architect, 1865–1934Photograph of one of their buildings · Lee Paxton · CC BY-SA 4.0 · Wikimedia Commons3 buildingsUnited StatesFurther readingWikipedia article↗BuildingsUnion Trust BuildingPittsburgh, United StatesWashington County CourthouseWashington, United StatesWestinghouse Air Brake Company General Office BuildingWilmerding, United States