Think tanks and research centers are great places to find research on policy and policy recommendations. Remember to always investigate their "About Us" page, donors, and contributors to be aware of any potential bias.
Use this checklist to determine if a source is appropriate:
Authority: Who wrote it? What credentials does s/he have? [PhD, affiliation with university]
Source: Where was it published? How was it selected for publication? [look at submission guidelines for evidence of peer review or other editorial processes]
Currency: When was it published? Has it appeared in other forms with/out revision?
Research: Are other sources cited in a bibliography/reference list? Are foot/endnotes used?
Bias: Is there an objective viewpoint? Is the author making assertions without documentation, or with questionable documentation? [e.g., her/his own work, crackpots]