Sorry... the way my comment relates to the articles you cited and to Dwaine's article is that, while recursion is a mathematically sound way of expressing a problem, none of them explain that the use of recursive CTEs is usually not a good way to solve the problem either performance wise or resource usage wise simply because of the way SQL Server does the recursion. I'd like to see folks start to take a little responsibility in that area by doing a resource usage and performance comparison between the rCTE's and the equivalent While Loops.