Right now, I'm working on my master's dissertation and it is great because I get to read all the school library research.
The American Association of School Librarian's scholarly journal: School Library Research is entirely open access which makes it a really useful tool to narrow the gap between research and practice. My favourite article is this one:
Small, Ruth V., Shanahan, Kathryn A. and Stasak, Megan. (2010) "The Impact of New York's School Libraries on Student Achievement and Motivation: Phase III." School Library Media Research Vol. 13.
It gives a really clear picture of the role of the school librarian in the 'elementary school'.