Book: Hutchins, Catherine E., et al. 1983 Arts of the Pennsylvania Germans.
• Published as pl. 40.Book: Earnest, Russell D. & Earnest, Corinne P. 1997 Papers for Birth Dayes: Guide to the Fraktur Artists and Scriveners. 2 vols. 909.
• Published on p. 467.Article: Weiser, Frederick S. 1988 "Ach Wie ist die Welt so Toll! The mad, lovable world of Friedrich Krebs.". Der Reggeboge: Journal of the Pennsylvania German Society. 22 (2): 49-88.
• Published as fig. 14.