National Geographic Magazine 1985-04, April
National Geographic Magazine 1976-11, November
National Geographic Magazine 1982-05, May
National Geographic Magazine 1972-07, July
National Geographic Magazine 1976-12, December
National Geographic Magazine 1972-01, January
National Geographic Magazine 1977-11, November
National Geographic 1993-10, October
National Geographic 1994-07, July
National Geographic Magazine 1989-11, November
National Geographic Magazine 1974-04, April
National Geographic Magazine 1990-12, December
National Geographic Magazine 1976-02, February
National Geographic 1995-04, April
National Geographic 1997-05, May
National Geographic Magazine 1982-06, June
National Geographic Magazine 1975-05, May
National Geographic Magazine 1976-10, October
National Geographic Magazine 1974-11, November
National Geographic 1996-12, December
National Geographic Magazine 1984-11, November
National Geographic 1996-06, June
National Geographic Magazine 1990-01, January
National Geographic Magazine 1981-03, March
National Geographic Magazine 1976-03, March
National Geographic Magazine 1986-06, June
National Geographic Magazine 1990-11, November
National Geographic Magazine 1973-09, September
National Geographic Magazine 1979-05, May
National Geographic 1992-10, October
National Geographic 1997-11, November
National Geographic Magazine 1980-08, August
National Geographic Magazine 1988-05, May
National Geographic Magazine 1989-04, April
National Geographic Magazine 1975-03, March
National Geographic Magazine 1985-05, May
National Geographic Magazine 1989-10, October
National Geographic Magazine 1987-05, May
National Geographic Magazine 1973-06, June
National Geographic Magazine 1976-09, September