What is Plagiarism

Are all published works copyrighted?
Actually, no. The Copyright Act only protects works that express original ideas or information. For example, you could borrow liberally from the following without fear of plagiarism:

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  Compilations of readily available information, such as the phone book
  
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  Works published by the U.S. government
  
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  Facts that are not the result of original research (such as the fact that there are fifty U.S. states, or that carrots contain Vitamin A)
  
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  Works in the public domain (provided you cite properly)