Lewis, R. A., Simmonds, P. E., Silver, T. M., Cheng, T., Henini, M. & Chamberlain, J. (1997). Far-infrared photoconductivity and photoluminescence of beryllium in gallium arsenide. Shallow-Level Centers in Semiconductors (pp. 257-262). Singapore: World Scientific, Singapore.
Lewis, R. A., Simmonds, P. E., Silver, T. M., Cheng, T., Henini, M. & Chamberlain, J. (1997). Far-infrared photoconductivity and photoluminescence of beryllium in gallium arsenide. Shallow-Level Centers in Semiconductors (pp. 257-262). Singapore: World Scientific, Singapore.