Controlling for Overdispersion in Grouped Conditional Logit Models: A Computationally Simple Application of Dirichlet-Multinomial Regression.
Paulo Guimarães, Richard Lindrooth
Econometrics Journal, vol. 10, 2007, p. 439-452.

Beyond the Silicon Valley: University R&D and High-Technology Location
Douglas Woodward, Octávio Figueiredo, Paulo Guimarães
Journal of Urban Economics, vol. 60, 2006, p. 15-32.