1
Published: June, 1969
Superior document: The National geographic magazine Vol. 135 (1969) No. 6 [Beilage 1]
2
Published: December, 1965
Superior document: The National geographic magazine Vol. 128 (1965) No. 6 [Beilage 1]
3
Published: December, 1970
Superior document: The National geographic magazine Vol. 137 (1970) 12 [Beilage 1]
4
Published: August, 1970
Superior document: The National geographic magazine Vol. 137 (1970) 8 [Beilage 1]
5
Published: Juni, 1969
Superior document: The National geographic magazine Vol. 136 (1969) 6 [Beilage 1]