1. Malaysia's Coal Resource: Opportunities and Challenges;Ambun,2003
2. American Standard for Material Testing (ASTM 2001), vols. 05–06, 2001.
3. Laboratory and modeling investigations of CO2 sequestration in coal at NETL;White,2004
4. Understanding the chemistry and physics of coal structure (a review);Levine;Proc. Natl. Acad. Sci. U.S.A.,1982
5. Earth Trend: The Environment Information Portal,2005