A convenient method for the preparation of mono- and bis-substituted photochromic bis(benzothienyl)perfluorocyclopentenes via regioselective Friedel–Crafts acylation [Текст] / N. S. Bogatishcheva, V. N. Yarovenko, K. S. Levchenko, O. I. Kobeleva, T. M. Valova, V. A. Barachevskii, M. I. Struchkova, P. S. Shmelin, M. M. Krayushkin, V. N. Charushin // Tetrahedron Letters. - 2012. - Vol.53, №44. - С. 5948-5951.