Infrared reflectivity and vibrational structure of superconducting 'BI IND.2''SR IND.2''CA''CU IND.2''O IND.8+X' - Piro, O E; Guida, J A; Massa, N E; Aymonino, P J; Castellano, Eduardo Ernesto; Basso, Heitor Cury; Gallo, Nelson José Heraldo; Martin, A A (Physical Review B, 1989)