1. “Functionalization of MWCNTs with atomic nitrogen : electronic structure”.  Ruelle B, Felten A, Ghijsen J, Drube W, Johnson RL, Liang D, Erni R, Van Tendeloo G, Dubois P, Hecq M, Bittencourt C;, Journal of physics: D: applied physics 41, 045202 (2008).   http://doi.org/10.1088/0022-3727/41/4/045202