SIMBAD references

It is difficult to accurately measure the effective gravity (logg) in late-type stars using broadband (e.g., UBV or SDSS) or intermediate-band (uvby) photometric systems, especially when the stars can cover a range of metallicities and reddenings. However, simple spectroscopic observational and data reduction techniques can yield accurate values for logg through comparison of the Balmer jumps of low-resolution spectra with recent grids of synthetic flux spectra.