Boonyarattanakalin, S., P. Bookong, and S. Ruchirawat. “Application and Process Development of Microwave Radiation for Etherification of Glycerol to Value-Added Polyglycerols”. Science & Technology Asia, vol. 20, no. 2, June 2015, pp. 33-43, https://ph02.tci-thaijo.org/index.php/SciTechAsia/article/view/35781.