Koch wrote a book containing 493 old-world symbols, monograms and runes entitled The Book of Signs (reprinted in 1955, in the Dover Pictorial Archive Series). He had also a column in the magazine Die zeitgemäße Schrift, a magazine of design published by Heintze & Blanckertz.
Types
Deutsche Schrift (1908-1921)
Maximilian Antiqua (1913-17)
Wilhelm Klingspor-Schrift (1920-1926)
Deutsche Zierschrift (1921)
Koch Antiqua / Locarno (1922), sold by Continental Type in the United States as Eve