I recently rediscovered Rothschild and Stiglitz's classic paper, "Equilibrium in Competitive Insurance Markets".
In footnote 7, they refer to an earlier version of their paper for details on the robustness of their results to their assumptions. Does anyone know how to track that version down? Many different Google search queries haven't worked.
The complete citation for the working paper is
Rothschild, M., and J. E. Stiglitz, "Equilibrium in Competitive Insurance Markets," Technical Report No. 170, IMSSS Stanford University, 1975.
On a separate note, the published version of their paper is beautifully written. You would be remiss to not have read it.