Unemployment and the Minimum Wage---what are the main counter-arguments to Card and Krueger?
Isaac Sorkin, a grad student at Michigan, has addressed this. Here is Miles Kimball blogging it, Isaac Sorkin: Don't Be Too Reassured by Small Short-Run Effects of the Minimum Wage, Jonathan Meer and Jeremy West: Effects of the Minimum Wage on Employment Dynamics, and The Economist—Destination Unknown: Large Increases in the Minimum Wage Could Have Severe Long-Term Effects. The main argument there is that previous work measures short run elasticities, which are less responsive than in the long run. You can surely find more by checking Sorkin's citations.