Robert, J., Miniatura, C., Perales, F., Vassilev, G., Bocvarski, V., Reinhardt, J., Baudon, J., & Lorent, V. (1989). Survival of Metastable Hydrogen-atoms Passing Through Crossed Electric and Magnetic-fields. Europhysics Letters : a letters journal exploring the frontiers of physics, 9(7), 651-656. https://doi.org/10.1209/0295-5075/9/7/007 (Original work published 1989)