Synthesis of 2,4-disubstituted furans and 4,6-diaryl-substituted 2,3-benzo-1,3a,6a-triazapentalenes - Katritzky, Alan R.; Hur, Deniz; Kirichenko, Kostyantyn; Ji, Yu; Steel, Peter J. (ARKIVOC, 2003)
doi: 10.3998/ark.5550190.0005.208