Ross 128 – GL 447 - A possible activity cycle for a slow-rotating fully convective star R. V. Ibañez Bustos, A. P. Buccino, M. Flores and P. J. D. Mauas A&A, 628 (2019) L1 Published online: 29 July 2019 DOI: 10.1051/0004-6361/201936030