Projection factor and radii of Type II Cepheids - BL Her stars P. Wielgórski, G. Pietrzyński, W. Gieren, B. Zgirski, M. Górski, J. Storm, N. Nardetto, P. Kervella, G. Bras, G. Hajdu et al. (7 more) A&A, 689 (2024) A241 Published online: 17 September 2024 DOI: 10.1051/0004-6361/202450182