1. W. Peschka, “Flüssiger Wasserstoff als Energieträger”, Springer Verlag Wien—New York, 1984
2. Pictures: Copyright of Archiv der Luftschiffbau Zeppelin GmbH, Friedrichshafen, FRG.
3. G. Daniel Brewer, “Hydrogen Aircraft Technology”, CRC Press, 1991, 5838, ISBN 0-8493-5838-8
4. DGLR/DFVLR International Symposium “Hydrogen in Air Transportation” September 11–14, 1974, Stuttgart, Germany
5. H.P. Alder “Hydrogen in Air Transportation. Feasibility Study for Zürich Airport, Switzerland”, International Journal of Hydrogen Energy, Vol. 12, No. 8, pp. 571–585, 1987