S.  Nagane and Ogale, S. B., ?CH3NH3Pb(BF4)(3) and (C4H9NH3)2Pb(BF4)(4) family of 3D and 2D perovskites without and with iodide and bromide ions substitution?, Journal of Physical Chemistry Letters, vol. 7, no. 22, pp. 4757-4762, 2016.