If you do not see a statement that the web page can be used freely, you need to not only cite the source properly but also obtain permission from the copyright holders. It may not be obvious whether or not something on the Internet is part of the public domain. The current copyright law does not require a notice of copyright on a document for it to be copyrighted. This rule holds for multimedia presentations that may later be posted on the Web. It also holds when students distribute their projects over electronic networks.