source : https://worldwide.espacenet.com/publicationDetails/originalDocument?DB=EPODOC&FT=D&date=18980219&CC=GB&NR=189709082A&KC=A
source : https://worldwide.espacenet.com/publicationDetails/originalDocument?DB=EPODOC&FT=D&date=18980219&CC=GB&NR=189709082A&KC=A