Pham Duc Tien. “Evaluation of Charcoal Floatability at Darkov Mine, Czech Republic and Comparison With Liquid Collectors Montanol 800, Flotakol NX, and Distilled Oil KODP1 from Wood-Chip Pyrolysis”. UTEHY Journal of Applied Science and Technology, Vol. 11, Oct. 2016, pp. 88-91, http://tapchi.utehy.edu.vn/index.php/jst/article/view/262.