Flares in open clusters with K2 - I. M 45 (Pleiades), M 44 (Praesepe), and M 67 Ekaterina Ilin, Sarah J. Schmidt, James R. A. Davenport and Klaus G. Strassmeier A&A, 622 (2019) A133 Published online: 07 February 2019 DOI: 10.1051/0004-6361/201834400