Introductory information about EEG/ERP methods using EGI dense-array apparatus can be found at EGI.com. EGI also offers several helpful workshops.
Child brain development as studied at CHGD via EEG/ERP and including state and ERD (even-related desynchronization) methods
Liu, D., Sabbagh, M. A., Gehring, W. J. & Wellman, H. M. (2009). Neural correlates of children’s theory of mind. Child Development, 80, 318-326
Bowman, L. C., Liu, D., Meltzoff, A. N., & Wellman, H. M. (2012). Neural correlates of belief- and desire-reasoning in 7- and 8-year-old children: an event-related potential study. Developmental Science, 15(5), 618-632.
Sabbagh, M. A, Bowman, L. C., Evraire, L. E., & Ito, J. M. B. (2009). Neurodevelopmental correlates of theory of mind in preschool children. Child development, 80, 1147-62.