B&W filed patents. Search on the U S Patent and Trademark Office site skip to http://patft.uspto.gov/netahtml/search-bool.html For term one, enter "barker & williamson" that returns http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=/netahtml/search-bool.html&r=1&f=G&l=50&co1=AND&d=ptxt&s1='Barker+Williamson'&OS= and so on