[1]JournaloftheAmericanChemicalSociety,1969,vol.91,p.7548-7550
[1]GazzettaChimicaItaliana,1977,vol.107,p.549-554
[1]JournaloftheAmericanChemicalSociety,1969,vol.91,p.7548-7550
[1]Tetrahedron,1986,vol.42,p.961-974
[1]TetrahedronLetters,1980,vol.21,p.2521-2524