GU Monocerotis: A high-mass eclipsing overcontact binary in the young open cluster Dolidze 25 J. Lorenzo, I. Negueruela, F. Vilardell, S. Simón-Díaz, P. Pastor and M. Méndez Majuelos A&A, 590 (2016) A45 Published online: 10 May 2016 DOI: 10.1051/0004-6361/201628224