Citation: Nicolas Mercier; Sylvain Poiroux; Am\'ed\'ee Riou; Patrick Batail (2004). Unique Hydrogen Bonding Correlating with a Reduced Band Gap and Phase Transition in the Hybrid Perovskites (HO(CH2)2NH3)2PbX4 (X = I, Br). Inorganic Chemistry, 43, pp. 8361-8366.