Mars Underground
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- Author: William K. Hartmann
- Language: English
- Year: 1997
- Author: Gerd Hartmann Geoffrey Coe Anne-Lies Ihme Gerd Werner Reiner Zieger
- Language: German
- Year: 1985
- Author: R.R.K. Hartmann Gregory James
- Language: English
- Year: 1998
- Author: Wilfried Hartmann
- Language: German
- Year: 2007
- Author: Hans Jurgen Korsch Hans-Jorg Jodl Timo Hartmann
- Language: English
- Year: 2008
- Author: Silvia Hartmann
- Language: English
- Year: 2003
- Author: Thomas de Hartmann Olga de Hartmann
- Language: English
- Year: 1992
- Author: Harald Schmalenberg Rainer Hartmann Walter Baumann
- Language: German
- Year: 2010
- Author: Jutta Hartmann
- Language: German
- Year: 2007