1996 , T.S. Golosinski & ‎Guo Yuguang, Mining Science and Technology 1996, The caking behaviour of vitrain and clarain could be improved after the coal has been picked out.
1997, Yang Qi, Geology of Fossil Fuels: Coal, In order to measure relatively accurately the activation energy of coal, and to exclude the disturbance from coal samples, the hand-picked banded vitrains in bright coal are adopted as experimental samples (Table 1).
2012 , C.E. Snape , Composition, Geochemistry and Conversion of Oil Shales , Thus, it may be concluded that a lower viscosity of plastic vitrain grains facilitates pores to grow and coalesce and grains to stick to one another to create intergrain pores.
