Spectroscopic characterization of the known O-star population in Cygnus OB2: Evidence of multiple star-forming bursts

1. Berlanas, S.R.
2. Herrero, A.
3. Comerón, F.
4. Simón-DÍaz, S.
5. Lennon, D.J.
6. Pasquali, A.
7. Maíz Apellániz, J.
8. Sota, A.
9. Pellerín, A.