George S. Webster and Samuel Tobias Wagner, “History of the Pennsylvania Avenue Subway, Philadelphia, and Sewer Construction Connected Therewith,” Transactions of the American Society of Civil Engineers, Volume XLIV (December 1900), pp. 1-33 and plates I – IV.

PDF version (printer-friendly).

N. S. Sprague and Chas. M. Reppert; “The Pittsburgh Sewer Explosion;” Engineering News; Vol. 71, No. 1 (January 1, 1914); pp. 22-28.

PDF

“Discharge of Inflammable Wastes Into Sewers – Problem of Prevention – The Pittsburgh Sewer Explosion Investigation,” Engineering and Contracting, Vol XLII, No. 21 (November 18, 1914), pp. 476-478.

PDF (scanned by Google Books)

Grant M. Olewiler, “Sewer Maintenance,” Sewage Works Journal, Volume IX, No. 5 (September 1937), pp. 808-820.

PDF version (printer-friendly).

A document entitled “Regulations for sewer Inspectors and Other Persons Engaged in Sewerage Work”.  This was published/released by the City of Philadelphia  on Mar 5, 1908.Source:  A website dedicated to the preservation of water and sewer history in the Philadelphia PA area …. www.phillyh2o.org.

PDF version (printer-friendly)