8Koay G F L,Abdullah L C ,Yunus R. Crystallization of dihydroxystearic acid (DHSA) produced from commercial grade palm oil based crude oleic acid employing isopropyl alcohol as solvent[J]. International Journal of Engineering and Technology, 2006,3(1) :115 -124.
9Meffert A, Wilk H C. Hydroxy fatty acid amides surfactants and uses [ P]. DE :3 638 918,1988.
10Roila A, Salmiah A, Kang Y B. Preparation of dihydroxy fatty acid from oleic acid [ P]. MY:9 804 456,1998.