Foucault cites Magdalene Humpert author of Bibliographie der Kameralwissenschaften (1937) in which the author makes note of a substantial bibliography was produced of over 4000 pieces of the practice of Polizeiwissenschaft however, this maybe a mistranslation of Foucault's own work the actual source of Magdalene Humpert states over 14,000 items were produced from the 16th century dates ranging from 1520-1850.