Biographical Sources contain
Academic or specialized Encyclopedias
These definitions are based on information from Katz, William A. Introduction to Reference Work. New York: McGraw-Hill, 1997. Print.
This page highlights a special type of information resources that librarians call "reference tools" or reference resources.
Not everything is not on the open Internet through search engines such as Google.
Many of the types of information sources such as reference material, periodical articles, books-were first published in print but now books and article begin their lives in a computer and are born digital and can be made available online. There are public and private area of the Internet. Google, Yahoo and Bing cannot find the private areas of information with a logon and password.