BW Beenau, DS Bonalle, SW Fields, WJ Gray… - US Patent …, 2009 - Google Patents
4,066,873. A 1, 1978 Schatz cation No. 10/192,488, filed on Jul. 9, 2002, now Pat. 4,119,361
A 10/1978 Greenaway No. 7.239, 226, which is a continuation-in-part of 4,202,491 A 5/1980 …