Stellar rotation periods determined from simultaneously measured Ca II H&K and Ca II IRT linesM. Mittag, A. Hempelmann, J. H. M. M. Schmitt, B. Fuhrmeister, J. N. González-Pérez and K.-P. SchröderA&A, 607 (2017) A87DOI: https://doi.org/10.1051/0004-6361/201630262
