Gibbons, Phebe Earle, Pennsylvania Dutch and Other Essays, Philadelphia, J.B. Lippincott, (OCLC128259577, lire en ligne)
Sachse, Julius Friedrich, The German Sectarians of Pennsylvania: A Critical and Legendary History of the Ephrata Cloister and the Dunkers, Philadelphia, Printed for the author, 1899–1900 (OCLC2030149)