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3. English translation published in Gen. Relativ. Gravit. vol. 32, pp. 1661 (2000)
4. Jordan, P., Ehlers, J., Kundt, W.: Strenge Lösungen der Feldgleichungen der Allgemeinen Relativitätstheorie, Akademie der Wissenschaften and der Literatur, Abhandlungen der Mathematisch-naturwissenschaftliche Klasse, Nr 2, pp. 21–105 (1960);
5. English translation published in Gen. Relativ. Gravit., vol. 41, pp. 2191–2280 (2009)