The contact binary VW Cephei revisited: surface activity and period variation T. Mitnyan, A. Bódi, T. Szalai, J. Vinkó, K. Szatmáry, T. Borkovits, B. I. Bíró, T. Hegedüs, K. Vida and A. Pál A&A, 612 (2018) A91 Published online: 03 May 2018 DOI: 10.1051/0004-6361/201731402