Figure 8 Comparison
of AAE and R 2  with results from previous
research data. Reprinted by permission from Yi, L.; Feng, J.; Qin,
Y.-H.; Li, W.-Y. Prediction of elemental composition of coal using
proximate analysis.  Fuel 2017, 193,  315–321. under a Creative Commons Attribution-Noncommercial
4.0 Unported License. Copyright 2017 Elsevier. High volatile bituminous
coal: HVBC and sub-bituminous coal: SBC.