Patent #5,074,437. Can be found here: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=5

Patent #5,074,437. Can be found here: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=5074437.PN.&OS=PN/5074437&RS=PN/5074437 http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=H...