Stata Tip 106: With or without Reference

Cox N. J. , Warburton J. , Armstrong A. , and Holliday V. J. 2008. Fitting concentration and load rating curves with generalized linear models. Earth Surface Processes and Landforms 33: 25–39.

Wooldridge J. M. 2010. Econometric Analysis of Cross Section and Panel Data. 2nd ed. Cambridge, MA: MIT Press.