Menstruationskalender
Über die Notwendigkeit kalendermäßiger Aufschreibung des Eintritts der Regelblutungen.
Menstrual cycle calender to record the first day of menstruation by Hermann Knaus.
First edition 1934, Vienna-Düsseldorf. The calender was published in numerous languages including French, English, Spanish, Dutch, Danish, Italian as well as Swedish.
Included is a counting rod indicating the fertile days.
