Papers and other research materials are accessible at abstract level, while full texts are retrievable only by an online pay-per-service feature. Limited external linking features.
Navigating and browsing are free as well as viewing abstracts, presentations of barometer surveys and book descriptions (with also tables of contents). Instead, full -text records of any kind are retrievable only with a online pay-per-service feature
Abstracts, annotations and other information are accessible for free
Efficient structure of internal linking, but with few links to related sites. No external links section is provided