REFERENCES 



115 



Ott, E., Spurlin, H. M. and Grafflin, M. W., (Editor), Cellulose and Cellulose 



Derivatives. High Polymers vol. V. Interscience, New York (1954). 

 Potonie, R., Petrographische Klassification der Bitumina. Geol. Jahrb. 65 



(1950). 

 Press, J. J. (Editor), Man-made fiber progress. Ann. N. Y. Acad. Sci. 67, 897-982 



(1957). 

 Roff, W. J., Fibres, Plastics and Rubbers. Butterworths, London (1956). 

 Tomkeieff, S. I., Coals and Bitumens. Pergamon Press, London (1954). 

 Waksman, S. A., Humus: Origin, Chemical Composition, and Importance in 



Nature. London, (1938). 

 Wise, L. E., Wood Chemistry. Reinhold, New York (1944). 

 Wood, H., Handbook No. 72, USDA Forest Service, USGPO, Washington 



(1955). 



