National Geographic 1997-03, March
National Geographic Magazine 1979-08, August
National Geographic Magazine 1982-12, December
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National Geographic Magazine 1982-07, July
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National Geographic 1991-02, February
National Geographic Magazine 1981-10, October
Geocaching Magazin – November-Dezember 06, 2013
National Geographic Magazine 1979-12, December
National Geographic Magazine 1984-01, January
National Geographic Magazine 1974-05, May
National Geographic Magazine 1973-05, May
National Geographic Magazine 1988-09, September
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National Geographic Magazine 1979-07, July
National Geographic Magazine 1989-07, July
National Geographic Magazine 1971-09, September
National Geographic 1991-01, January
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National Geographic Magazine 1987-11, November
National Geographic Magazine 1972-04, April
National Geographic Germany – Januar 01, 2014
National Geographic Magazine 1983-06, June
National Geographic Magazine 1981-09, September
National Geographic 1995-05, May
National Geographic 1993-SE (Special Edition)
National Geographic 1994-08, August
National Geographic Magazine 1983-03, March
