@techreport{RueeggESvH15, author = {Ulf R{\"u}egg and Thorsten Ehlers and Miro Sp{\"o}nemann and Reinhard von Hanxleden}, title = {A Generalization of the Directed Graph Layering Problem}, institution = {Kiel University, Department of Computer Science}, type = {Technical Report}, note = {{ISSN 2192-6247}}, number = {1501}, month = {February}, year = {2015}, pdf = {report-1501.pdf}, }