National Geographic Magazine 1981-02, February (Special Report)
National Geographic 1994-12, December
National Geographic Magazine 1976-07, July
National Geographic 1994-03, March
National Geographic Magazine 1987-04, April
National Geographic Magazine 1974-09, September
National Geographic 1993-03, March
National Geographic Magazine 1977-12, December
National Geographic Magazine 1971-07, July
National Geographic Magazine 1977-10, October
National Geographic 1994-11, November
National Geographic 1997-07, July
National Geographic Magazine 1979-11, November
National Geographic Magazine 1989-12, December
National Geographic Magazine 1984-06, June
National Geographic Magazine 1973-04, April
National Geographic 1995-09, September
National Geographic Magazine 1978-08, August
National Geographic Magazine 1987-01, January
National Geographic Magazine 1985-07, July
National Geographic Magazine 1979-01, January
National Geographic Magazine 1975-06, June
National Geographic Magazine 1989-08, August
National Geographic Magazine 1987-07, July
National Geographic Magazine 1990-07, July
National Geographic Magazine 1971-01, January
National Geographic Magazine 1982-09, September
National Geographic Magazine 1976-04, April
National Geographic 1997-03, March
National Geographic Magazine 1979-08, August
National Geographic Magazine 1982-12, December
National Geographic Magazine 1985-10, October
National Geographic 1992-08, August
National Geographic Magazine 1990-08, August
National Geographic 1996-05, May
National Geographic Magazine 1972-03, March
National Geographic Magazine 1979-09, September
National Geographic Magazine 1977-06, June
National Geographic Magazine 1988-10, October
National Geographic Magazine 1981-07, July
