1. Localisation, caracterisation et classification petrographique des substances organiques sedimentaire fossiles;Alpern,1972
2. A progress report on the Alpern Coal Classification;Alpern;Int. J. Coal Geol.,1989
3. The calculation of coking charges on the basis of the petrographical characteristics of coals;Ammosov;Kots Khim.,1957
4. Use of the AMEDA microscope in quantitative microscopy;Bayer;Am. Soc. Testing Materials, Spec. Techn. Publ.,1968
5. Pseudovitrinite in Appalachian coking coals;Benedict;Fuel,1968