4MAUL, JAMES J. Process for the preparation of halo aromatic compounds : Eur, 180057 [ P]. 1986-05-07.
5BROWN S J, CLARK J H. The fluorination of organic substrates with tetraphenyl-phosphonium hydrogendiflouride [ J]. Journal of Fluorine Chemistry, 1985,30( 3 ) : 251-258.