( 5 ) Stach , E. , Fuel , Vol . 34 , 1955 , pp . 95-118 . [ 6 ] Stach , E. , Mackowsky , M.-Th. , Teichmüller , M. , Taylor , G. H. , Chandra , D. , and Teichmüller , R. , Stach's Textbook of Coal Petrology , Gebrüder Borntraeger ...