The Water Supply Problem of Philadelphia, 1899
Diagram Showing Decreased Amount of Dissolved Oxygen in Delaware River, 1913
Bacteria in Delaware River, Torresdale Filters, 1913
Water, Water Everywhere – Philadelphia Record, 1937-03-14
Commencement of laying the main on the East side of the River, 1871
Allegheny Avenue Sewer at Pier 126, 1918