Article: Evans, Nancy Goyne. 02//1973 Documented Fraktur in the Winterthur collection, Part I. Antiques. 103 (2): 307-18.
• Published as fig. 9, p. 312 and 314.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.
• For a complete four panel set of the Prodigal Son by Krebs, see pp. 76-79.Book: Earnest, Russell D. & Earnest, Corinne P. 1997 Papers for Birth Dayes: Guide to the Fraktur Artists and Scriveners. 2 vols. 909.
• For information on Friedrich Krebs, see pp. 460-467.