Electronic spectra and structure of conjugate acids of carbonyl derivatives of pyrrole - Struchkova, M I; Gusarov, A N; Dvoryantseva, G G; Evstigneeva, R P; Ioslovich, N V; Kabankin, A S; Kaganskii, M M; Landau, M A (Chem Heterocycl Compd, 1977)