SIMBAD references

We compare the evolution of spectral shape with luminosity in GRS 1915+105 with that of `normal' black holes. The pathological variability of GRS 1915+105, which probably indicates a disc instability, does not require that GRS 1915+105 belongs in a different class to all the other objects. At comparable fractions of Eddington luminosity its spectra and (more importantly) apparent disc stability are both similar to that seen in the `normal' black holes. Its unique limit-cycle variability only appears when it radiates at uniquely high (super-Eddington) luminosities.