Kolevzon, Edward R.
Our world and its people
Allyn and Bacon, 1959
 Buku Teks SO
Gaunt, Jeremy
Our world now : Reuters
Thames & Hudson, 2010
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Garland, John K.
Chemistry of our world
Macmillan, 1975
 Buku Teks SO
Garland, John K.
Chemistry of our world
Macmillan, 1975
 Buku Teks SO
Inventors and discoverers : changing our world
National Geographic Book Service
National Geographic Society, 1988
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