1. Newton J. M. D. Chulia, M. Deleuil, Y. PourcelotExtrusion/spheronisation, in Powder Technology and Pharmaceutical Processes, Elsevier, New York 1994; 391–401
2. Fielden K. E., Newton J. M. J. Swarbrick, J. C. BoylanExtrusion and extruders, in Encyclopedia of Pharmaceutical Technology, Marcel Dekker Inc., New York and Basel 1992; 395–442