Disclaimer. Don't rely on these old notes in lieu of reading the literature, but they can jog your memory. As a grad student long ago, my peers and I collaborated to write and exchange summaries of political science research. I posted them to a wiki-style website. "Wikisum" is now dead but archived here. I cannot vouch for these notes' accuracy, nor can I even say who wrote them. If you have more recent summaries to add to this collection, send them my way I guess. Sorry for the ads; they cover the costs of keeping this online.
Krueger. 1974. The political economy of rent-seeking. American Economic Review 3: 291-303.
Y = welfare/deadweight loss (from rent seeking)
X = competitiveness of rent-seeking, as defined by the nature of import restrictions
Main point: all capitalist societies have rents. These rents impose costs on society, but they impose even greater costs when the system invites competition for these rents.
Research on similar subjects