John Eyerman, The Old Grave-Yards of Northampton and Adjacent Counties in the State of Pennsylvania. Easton: Oakhurst House (private press).
Preston Barba, Pennsylvania German Tombstones: A Study in Folk Art. Allentown: Schlechter’s for the Pennsylvania German Folklore Society, 1954.
Preston A. Barba “Symbols and Stones.” Pennsylvania History: A Journal of Mid-Atlantic Studies 23, no. 2: pp. 241-47. http://www.jstor.org/stable/27769646.
Frank E. McDonald, “Pennsylvania German Tombstone Art of Lebanon County, Pennsylvania” in Pennsylvania Folklife, Autumn, Vol. XXV, No. 1, pp. 2-19.
William N. Richardson, “The Pennsylvania German Tombstones of Isaac Faust Stiehly (1800-1869),” Proceedings of the Northumberland County Historical Society, Vol. XXX. Also issued separately.
Claire Messimer, Known by the Work of His Hands. (Kutztown: Pennsylvania German Society annual volume.
Richard J. Mammana, Jr., “Interview With Sandra Hardy, Founder of Pennsylvania German Tombstones Online,” Der Reggeboge 38, no. 2, pp. 27-30.
Bernard L. Herman, “On Being German in British America: Gravestones and the Inscription of Identity.” Winterthur Portfolio 45, no. 2/3: 195-208. doi:10.1086/660910.
Alexander Lawrence Ames, “Quill and Graver Bound: Frakturschrift Calligraphy, Devotional Manuscripts, and Penmanship Instruction in German Pennsylvania, 1755–1855,” Winterthur Portfolio 50, no. 1 (Spring): pp. 1-83. doi:10.1086/687271