L. L. Sousa, I. L. Lucena and F. A. N. Fernandes, “Transesterification of Castor Oil: Effect of the Acid Value and Neutralization of the Oil with Glycerol,” Fuel Processing Technology, Vol. 91, No. 2, 2010, pp. 194-196.
http://dx.doi.org/10.1016/j.fuproc.2009.09.016

has been cited by the following article:

• TITLE: Pre-Treatment of High Free Fatty Acids Oils by Chemical Re-Esterification for Biodiesel Production—A Review

  AUTHORS: Godlisten G. Kombe, Abraham K. Temu, Hassan M. Rajabu, Godwill D. Mrema, Jibrail Kansedo, Keat Teong Lee

  KEYWORDS: Chemical Re-Esterification; High Free Fatty Acid; Glycerolysis; Biodiesel Feedstock

  JOURNAL NAME: Advances in Chemical Engineering and Science, Vol.3 No.4, October 28, 2013

  ABSTRACT: Non edible oil sources have the potential to lower the cost of biodiesel. However, they usually contain significant high amounts of free fatty acids (FFA) that make them inadequate for direct base catalyzed transesterification reaction (where the FFA content should be lower than 3%). The present work reviews chemical re-esterification as a possible method for the pre-treatment of high FFA feedstock for biodiesel production. The effects of temperature, amount of glycerol, type and amount of catalyst have been discussed. Chemical re-esterification lowers FFA to acceptable levels for transesterification at the same time utilizing the glycerol by product from the same process. Further researches have been proposed as a way forward to improve the process kinetics and optimization so as to make it more economical.