Trill fingerings from his Schule für Flöte.
(Publ. by Zimmermann, Zimmermann-Schule Nr. 53, Frankfurt, early 20C.)
Included as a removable folded insert in the one of my copies of Koehler's Schule is the following Tabelle für die gebräuchlichsten Triller. The chart was presumably inserted by the publisher, without any endorsement by Koehler, of course.