Dapp, C. F. (1919). History of Zion's or Old organ church: With a record of baptisms and biographical sketches of former pastors, founded by Muhlenberg in 1743, by the Rev. Chas. F. Dapp. Spring City, PA: Inter-borough press.

Dapp, Charles Frederick. History of Zion's or Old Organ Church: With a Record of Baptisms and Biographical Sketches of Former Pastors, Founded By Muhlenberg in 1743, By the Rev. Chas. F. Dapp. Spring City, PA: Inter-borough press, 1919.

Dapp, Charles Frederick. History of Zion's or Old Organ Church: With a Record of Baptisms and Biographical Sketches of Former Pastors, Founded By Muhlenberg in 1743, By the Rev. Chas. F. Dapp. Spring City, PA: Inter-borough press, 1919.