1
Published: December, 1976
Superior document: The National geographic magazine 94 (1976) 12 [Beilage 1]
2
Published: December, 1956
Superior document: The National geographic magazine 72 (1956) 12 [Beilage 1]
3
Published: December, 1976
Superior document: The National geographic magazine 93 (1975) 12 [Beilage 1]