M. Hairul Bahri, W. Wijayanti, N. Hamidi, and I. N. G. Wardana, “The role of alkali metal and alkaline metal earth in natural zeolite on combustion of Albizia Falcataria sawdust”, Int. J. Energy Environ. Eng., vol. 11, no. 2 (June 2020), Jan. 2020, doi: 10.1007/s40095-019-00323-2.