↑ M. Mendelssohn: Handbook of coin, measure and weight, taking into account the new coin and weight system, with detailed reduction tables. Horvarth'sche Buchhandlung, Potsdam 1859, p. 52
^ Eduard Döring: Handbook of coin, exchange, measure and weight. Verlag J. Hölscher, Koblenz 1862, p. 215