This is the default. A fee is required to access materials. When this symbol follows the symbol, it indicates a membership fee is required. When it follows a symbol indicating the type of materials at the site, it indicates a per-item access fee. This is similar to the symbol, but indicates the fee is nominal.
Membership is required to access materials.
Similar to , but indicates the non-member access is very limited. Time restricted access, usually to off-peak hours. The site is a business which sells products or services. Absence of the symbol indicates that the product or service can be ordered on-line. The type of product or service is indicated by the symbols below and in the Product section.