1. https://www.etymonline.com/search?q=coal. Accessed 20 Dec 2022
2. Robl T, Oberlink A, Jones R (2017) Coal combustion products (CCPs) – characteristics, utilization and beneficiation 3–20, Woodhead Publishing, p 564
3. Crelling JC (1989) The nature of coal material In: Introduction to carbon science. In: Marsh H et al (eds.), Butterworth-Heinemann, pp 259‒284
4. Blander M, Sinha S, Pelton A, Eriksson G (1989) Calculations of the influence of additives on coal combustion deposits. Am Chem Soc Div Fuel Chem 34:340–346 (Preprints of papers)
5. Rahman R, Widodo S, Azikin B, Tahir D (2019) Chemical composition and physical characteristics of coal and mangrove wood as alternative fuel. J Phys Conf Ser 1341:052008