B. Murachman, S. Sarjono, F. Afandi, and J. Khaeri, “Optimization Study of the Solid Propellant (Rocket Fuel) Based on Extracted Bitumen of Indonesian Natural Buton Asphalt”, ASEAN J. Chem. Eng., vol. 13, no. 2, pp. 57-72, Dec. 2013.