Poschenrieder, W., Behringer, K., Bosch, H. S., Field, A., Kallenbach, A., Kaufmann, M., et al. (1995). Molecular impurities in ASDEX UPGRADE plasma discharges. Journal of Nuclear Materials, 220-222, 36-49. doi:10.1016/0022-3115(94)00445-5.