To search for books on China's foreign policy, generally or with a specific country, use the Advanced Search to the right of the library search box. Select Library Catalog, change "any field" to "subject" and enter china foreign relations [name of country].
You can filter results by "held by library" for print books or "available online" and by date of publication.
For books on China's foreign policy in general, just search 'china foreign relations' (no quotes) in the subject field.
Other useful subject headings include
Other strategies to help identify grey literature include:
If you're not familiar with the think tank, IGO, NGO, etc., it's useful to review the About Us section of their website and look for other views about the organization in order to place their work in context and better evaluate the authority and credibility of their work.
The following are compilations of translated primary sources.