fair use
Fair use denotes the conditions under which copyrighted material can be used without requiring permission from the rights holder, such as for commentary, criticism, news reporting, research, teaching or scholarship purposes. Other works, such as those of the public domain, are also able to be used without explicit consent by a copyright holder, as these works are no longer protected under copyright. Be careful though- just because something is publicly available (ie. posted on the web), doesn't mean that it is part of the public domain! You should always assume that copyright exists, even when it is not directly stated.
While permission is not required for the use of these materials from the public domain it is important to note that the declaration of use is still required. Failure to acknowledge the author or creator of a given work is considered plagiarism, and may offer grounds for legal charging.
Make sure that you are familiar with the laws governing information use. It is important to acknowldege that even if you do not understand what plagiarism or copyright law is, you are still responsible for acts of intellectual theft or fraud found in your work.
