Four-month chromospheric and coronal activity cycle in τ BoötisM. Mittag, J. Robrade, J. H. M. M. Schmitt, A. Hempelmann, J. N. González-Pérez and K.-P. SchröderA&A, 600 (2017) A119DOI: https://doi.org/10.1051/0004-6361/201629156
