The Impact of Product Differentiation on Retail Bundling in a Vertical Market
A.E. Endres-Fröhlich, B. Hehenkamp, J. Heinzel, The Impact of Product Differentiation on Retail Bundling in a Vertical Market, n.d.

Bundling in a Distribution Channel with Retail Competition
J.M.J. Heinzel, Bundling in a Distribution Channel with Retail Competition, CIE Working Paper Series, Paderborn University, 2019.