The Brookings Institution
Access 
Open and free access to an extremely high quantity of materials directly provided or authored by Brookings Institute with broad possibility for browsing, search and downloading.
Fee Policy 
A completely open and freely accessible website
Free Retrieved Material
Material is almost always full-text retrievable in pdf format or in image page format. Sometimes, where available, also audio/video formats are retrievable for free
Linking Richness
The internal linking feature is highly developed, relating all branches of the Brookings Institute with each other and with external resources, which are also present and pertinent although not very numerous