Flares in open clusters with K2 - I. M 45 (Pleiades), M 44 (Praesepe), and M 67Ekaterina Ilin, Sarah J. Schmidt, James R. A. Davenport and Klaus G. StrassmeierA&A, 622 (2019) A133DOI: https://doi.org/10.1051/0004-6361/201834400