Linear polarization in the nucleus of M87 at 7 mm and 1.3 cm E. Kravchenko, M. Giroletti, K. Hada, D. L. Meier, M. Nakamura, J. Park and R. C. Walker A&A, 637 (2020) L6 Published online: 15 May 2020 DOI: 10.1051/0004-6361/201937315