Structural changes from heating amber and copal as observed by nuclear magnetic resonance spectroscopy
2019 ◽
pp. 157-181
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2010 ◽
pp. 1-7
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2013 ◽
Vol 40
(12)
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pp. 1933-1937
1981 ◽
Vol 640
(3)
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pp. 727-733
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