edited by B.M. Willet
George Philip and Son, 1981
Buku Referensi
George Philip & O'Neil, 1981
Buku Referensi
Foreword by William R. Mead
Tiger Book International, 1995
Buku Referensi
Lye, Keith, author
The Royal Geographical Society, 2000
Buku Referensi
Kidron, Michael, author
Simon & Schuster, 1984
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