Sunspots") in: Abhandlungen des naturwissenschaftlichen Vereins zu Bremen, 10, 1888, pp. 249–272. Bernhard Bunte: "Über Johannes Fabricus, den Entdecker der Sonnenflecken" ("On Johannes Fabricius, the Discoverer of Sunspots") in: Jahrbuch der Ges. für bildende Kunst und vaterländ. Altertümer zu Emden, 9, H. 1, 1890, pp. 59–77. Diedrich Wattenberg: David Fabricius. Der Astronom Ostfrieslands (David Fabricius. Astronomer of East Friesland), Berlin 1964. Fritz Krafft: in Walther Killy's Literaturlexikon: Autoren und Werke deutscher Sprache (Literature-Lexicon: Authors and Words of German Language), 15 volumes, Gütersloh; München: Bertelsmann-Lexikon-Verl. 1988-1991 (CD-ROM Berlin 1998 ), Vol. 3. Wilfried Schroeder, The Discovery of Sunspots, Bremen 2009 External links The Galileo Project — biography of David and Johannes Fabricius. Entry in the biographical encyclopedia of East Frisia (German) Celebrating 400 Years of Sunspot Observations. 1587 births 1616 deaths East Frisians Frisian scientists 17th-century German astronomers Leiden University alumni People from Aurich (district)