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3. Catalogue of the Third International Rubber and Allied Trades Exhibition. New York, 191 a.

4. C Christy. The African Rubber Industry and Funtumia elastica. 1911

5. Circulars and Agricultural Journal of the Royal Botanic Gardens, Ceylon. 1898-1911.

6. J. Collins. On the Commercial kinds of Indiarnbber. Journal of Botany. 1868.

7. British Manufacturing Industries, Guttapercha and Indiarubber. 1876.

8. Encyclopedia Britannica, ninth edition, Article on Indiarubber.

9. Sir Clements Markham. The Cultivation of Caoutchouc-yielding Plants in British India. Journal qf the Society of Arts. 1876.

10. Sir Daniel Morris. Sources of Commercial India-rubber, Cantor Lectures. Journal of the Society of Arts. 1898.

11. T. Pbtch. The Physiology and Diseases of Hevea brasiliensis. 1911. is. Philip Schidrowitz. Rubber. 1911.

13. Carl Otto Weber. The Chemistry of India Rubber. 1901.

14. J. C. Willis. Agriculture in the Tropics. 1909.

15. Herbert Wright. Hevea brasiliensis or Para Rubbert fourth edition, 191 a.

16. The Tropical Agriculturist to 1912.