[1]Patent:US5707989,1998,A,
[2]Patent:US5821240,1998,A,
[3]Patent:US5977102,1999,A,
[1]CanadianJournalofChemistry,1956,vol.34,p.1444
[1]Patent:US5821240,1998,A,
[1]Patent:US5977102,1999,A,
[1]Patent:US5821240,1998,A,
[1]CanadianJournalofChemistry,1956,vol.34,p.1444
[1]Patent:US2826580,1955,
[1]Patent:US2826580,1955,
[1]Patent:US2826580,1955,
[1]Patent:US2826580,1955,