Period change of massive binaries from combined photometric and spectroscopic data in Cygnus OB2Jaan Laur, Elmo Tempel, Taavi Tuvikene, Tõnis Eenmäe and Indrek KolkaA&A, 581 (2015) A37DOI: https://doi.org/10.1051/0004-6361/201526520
