Allen, S. J, K.  Craig, C. L Felix, P.  Guimaraes, J. N Heyman, J. P Kaminski, B. J Keay, et al.. ?Probing Terahertz Dynamics In Semiconductor Nanostructures With Ucsb Free-Electron Lasers?. Journal Of Luminescence 60-1 (1994): 250-255. doi:10.1016/0022-2313(94)90142-2.

Morris, D. E, J. H Nickel, J. YT Wei, N. G Asmar, J. S Scott, U. M Scheven, C. T Hultgren, et al.. ?8 New High-Temperature Superconductors With The 1-2-4 Structure?. Physical Review B 39 (1989): 7347-7350. doi:10.1103/physrevb.39.7347 .