1. BSEN14538/2006. Fat and oil derivatives. Fatty acid methyl ester (FAMEs). Determination of Ca, K, Mg, and Na content by opticalemission spectral analysis with inductively coupled plasma (ICP-OES).
2. American society of testing materials, ASTM D 6751.
3. Agência Nacional de Petróleo (Brazil), Gás Natural e Biocombustíveis, Resolução n. 14, 11.5.2012 – DOU 18.5.2012.
4. Contaminantes em Biodiesel e Controle de Qualidade;De Quadros;Rev Virtual Quim,2011
5. Electrochemical determination of inorganic contaminants in automotive fuels;Santos;Electroanalysis,2012