The Bibliographic Database of German Publication on Russia, the Soviet Union and its Successor States (RussGus)

The Bibliographic Database of German Publication on Russia, the Soviet Union and its Successor States (RussGus) contains about 170.000 records from 1974 to 2003 and collects publications of different document types: books, dissertations and other university publications, articles from journals and newspapers including reviews, maps etc. The lists of personal and geographical subjects are located here and here.

Your search for Pörtner, Rudolf provides 4 hits
1	Wolfgang Schwarz: Kosaken. Untergang eines Reitervolkes Pörtner, Rudolf, in: Die Welt, 17.04.1976, 91 (Rezension)
2	Klaus J. Gröper: Die Geschichte der Kosaken. Wilder Osten 1500-1700 Pörtner, Rudolf, in: Die Welt, 17.04.1976, 91 (Rezension)
3	Die Wikinger-Saga. Pörtner, Rudolf, Düsseldorf, Wien: Econ 1977, 454 S.
4	Leskov, Alexander: Grabschätze des Adygeen. Pörtner, Rudolf, in: Die Welt, 15.09.1990, 216, S. 19 (Rezension)

The Bibliographic Database of German Publication on Russia, the Soviet Union and its Successor States (RussGus)

Wolfgang Schwarz: Kosaken. Untergang eines Reitervolkes

Klaus J. Gröper: Die Geschichte der Kosaken. Wilder Osten 1500-1700

Die Wikinger-Saga.

Leskov, Alexander: Grabschätze des Adygeen.