Richards, G. T., Croom, S. M., Anderson, S. F., Bland-Hawthorn, J., Boyle, B. J., De Propris, R., …York, D. G. (2005). The 2dF-SDSS LRG and QSO (2SLAQ) Survey: the z < 2.1 quasar luminosity function from 5645 quasars to g= 21.85. Monthly Notices of the Royal Astronomical Society, 360, 839-852. https://doi.org/10.1111/j.1365-2966.2005.09096.x