Hori, M., Aghai-Khozani, H., Soter, A., Dax, A., & Barna, D. (2021). Laser Spectroscopy Measurements of Metastable Pionic Helium Atoms at Paul Scherrer Institute. Few-Body Systems, 62(3): 63. doi:10.1007/s00601-021-01630-3.