@Wodie,
An original document signed by the originator is a legal copy right, if you can prove it in a court of law. If you produce a document at your place of employment it all depends on what you signed when you were hired. Many companies make you sign a waver that says everything you create while employed on or off campus becomes the property of the employer. If you receive grants for school, beware of the agreements you sign. I had a client whose wife while working on her doctorate invented the LED. Because she signed and agreement with the company who granted her the funds she lost all rights. The best method is to exercise care about what you sign and register your work with the US Copy Right Office. However, this will not guarantee theft by unscrupulous individuals or court battles with large companies who use it to make a profit. Be smart and protect yourself.