"Helical Barrel Rheometer", D.B. Todd, C.G. Gogos, D. Charalampopoulous, US Patent 5,708,197, (1998).

"Back Mixed Drag Flow Apparatus", J.A. Biesenberger, D.B. Todd, US Patent 5,372,418, (1994).

"Method of Preparing Thermoplastic Foams using a Gaseous Blowing Agent", J.A. Biesenberger, S.K. Dey, and D.B. Todd, US Patent #5,707,573, (1998).