Niklas Luhmann ; translated by Klaus A. Ziegert ; edited by Fatima Kastner ... [et al.] ; with an introduction by Richard Nobles and David SchiffOxford University Press2008, c2004
Niklas Luhmann ; translated by Klaus A. Ziegert ; edited by Fatima Kastner ... [et al.] ; with an introduction by Richard Nobles and David SchiffOxford University Press2004
Eugen Ehrlich ; with an introduction by Roscoe Pound ; with a new introduction by Klaus A. Ziegert ; [translated by Walter L. Moll]Transaction Publishersc2002