Jacob, W. Surface Science (OP), Max Planck Institute for Plasma Physics, Max Planck Society;
Grigull, S., Jacob, W., Henke, D., Mucklich, A., Spaeth, C., & Summchen, L. (1997). On the presence of molecular nitrogen in nitrogen-implanted amorphous carbon. Applied Physics Letters, 70(11), 1387-1389. doi:10.1063/1.118585.