1. R. Barker, A. Saffer, US 2,833,816 (1955) to Mid-Century Corp.
2. J. Allen, E. Malmberg, US 3,235,615 (15 February 1966) to Sun Oil.
3. R. Barbor, E. Malmberg, US 3,565,945 (23 February 1971) to Sun Oil.
4. K. Ogata, K. Shimosato US 3,671,578 (20 June 1972) to Teijin Ltd.
5. G. Eberhardt, US 3,244,758 (5 April 1966) to Sun Oil.