Sales: Tests of Theories on Causality and Timing
Peter Berck, Jennifer Brown, Jeffrey Perloff, Sofia Villas-Boas
International Journal of Industrial Organization, vol. 26, 2008, p. 1257-1273.

Effects of sales on Brand Loyalty
Rui Huang, Jeffrey Perloff, Sofia Villas-Boas
Journal Of Agricultural And Food Industrial Organization, vol. 4, 2006, p. 1-0.