@article {2011ApJ...728..155D, title = {Direct Evidence for an Enhancement of Helium in Giant Stars in Omega Centauri}, journal = {\apj}, volume = {728}, number = {2}, year = {2011}, month = {feb}, pages = {155}, keywords = {Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics, globular clusters: general, globular clusters: individual: Omega Centauri, stars: abundances, stars: Population II}, doi = {10.1088/0004-637X/728/2/155}, author = {Dupree, A.~K. and Strader, Jay and Smith, Graeme H.} }