1. Hans-Joachim Albinus and Detlef Suckrau. Johannes Kepler in Ulm revisited: new aspects of old known facts. Mathematical Intelligencer 43:1 (2021), 64–77.
2. M. W. Burke-Gaffney. Kepler and the Jesuits. Bruce, Milwaukee, 1944.
3. Max Caspar. Johannes Kepler, edited and translated by C. Doris Hellman, 2nd ed. Dover, New York, 1993.
4. Walther Gerlach. Humor und Witz in Schriften von Johannes Kepler. Sitzungsberichte Bayerische Akademie der Wissenschaften. Mathematisch-Naturwissenschaftliche Klasse 1968, 13–30.
5. Johannes Kepler. Gesammelte Werke, 22 vols. (in 26). Beck, München, 1937–2017.