机译:Extending the red giant branch versus metallicity calibration toward metal-poor systems: Near-infrared photometry of the Galactic globular clusters M56 and M15
Univ Arizona, Steward Observ, 933 N Cherry Ave, Tucson, AZ 85721, USA.;
Color-magnitude diagrams; Globular clusters : individual (liller 1; m15; m56; ngc 6553; ngc 7099); Stars : population ii; Array photometry; Color-magnitude; Standard stars; Ages; M92;