The Theory of Interstellar Trade
OK, yes, I like this: New York Times columnist Paul Krugman's 1978 "paper" entittled "The Theory of Interstellar Trade" (PDF). (His blog post linked it last week.)
There are some good lines in there, including a citation of a later paper by the same author, a note of the difference between "relative generality" (of theorems) and "general relativity" (a physical theory).
Sadly, it seems the basic assumption—that the two trading planets are in the same inertial references frame—oversimplifies, and the central results seem to be that, since the trading end-points remain stationary in this frame, insterstellar trade is no different from international or interplanetary trade.