Books can offer a broader scope and context, and a lot of scholarly country studies are published as books.
Written by organizations like think tanks, NGOs, and government agencies, policy papers are reports on a policy topic that seeks to argue for a specific policy position with supporting research. Be sure to evaluate the organization that produces the policy paper to know if its authoritative.
If searching within a specific organization's website, a Google site search (see below) makes research much faster.
Organisation for Economic Cooperation & Development publications