Hans-Jürgen Krock, Manfred J. Zapka;
The Hawaiian International Hydrogen Energy Pilot Project: A Concept For The Commercial Implementation Of Non-Fossil Hydrogen Energy In The Pacific Ocean Area, Proceedings of IEEE OCEANS'91 Conference,
p. 224, October 1991.
Frank Benevides Jr., Manfred Zapka;
A Prototype Trim Draft Speed Indicator (TDSI) System For Small Waterplane Area Twin Hull (SWATH) Ships, Proceedings of IEEE OCEANS'91 Conference,
pp. 266 - 273, October 1991.