Discrete time normalized low pass filters: (Design tables, pocket calculator programs, Catalog of Butterworth, Chebychev and Cauer Filters) by Dr. Arild Lacroix and Heinrich Hertz, Institut für Nachrichtentechnik, Berlin, Fed. Rep. Germany, and Karl Heinz Witte, Institut für Übertragungstheorie, Technische Hochschule, Darmstadt, Fed. Rep. Germany. Publisher: Dr. Alfred Hütig Verlag GmbH, Postfach 102869, D-6900 Heidelberg, Fed. Rep. Germany, 1980, 334 pp., ISBN 3-7785-0623-4