I've never found an article that wasn't already preaching to the converted....instead I would ask, in writing, for a reading test to determine what the child's actual reading level is. (Common practice is to test a grade or two up and then stop, because, afterall, 'what difference does it make')
I would suggest that your friend down load the davidson manual on advocacy, and put together a portfolio of work that shows how the child compares to the 'scope and sequence' documents for her school - and ask for the school to start testing for a gradeskip. Even if your friend is totally against the skip, having the child evaluated for a gradeskip is the best way to let the school folks 'see for themselves' that they aren't dealing with a run of the mill gifted child.
Best wishes,
Grinity