1. E. J. Barth, “Asphalt Science and Technology”, Gordon and Breach Science Publishers, New York (1962).
2. J. Schwager and T. F. Yen, Coal-liquefaction Products from Major Demonstration Processes. 1, Separation and Analysis, Fuel 57:100 (1978).
3. K. H. Altgelt, D. M. Jewell, D.R. Latham, and M. L. Selucky, Chromatography in petroleum analysis, in.: “In Chromatographic Science Series,” K. H. Algelt and T., ed., Marcel Dekker Inc., New York and Basel (1979).
4. Y. Y. Wang and T. F. Yen, Application of Thin-Layer Chromatographic Identification of heavy Fractions of Fossil Fuels, ACS Pacific Conference on Chemistry and Spectroscopy. Pasadena (1989).
5. T. F. Yen, Asphaltic Materials, in: “Encyclopedia of Polymer Science and Engineering,” M. Grayson and J. I. Krochwitz, ed., Wiley, New York (1988).