Interviews, telephone conversations, email, letters and lectures are oral sources while usenet groups are treated as printed electronic sources. When it comes to references to oral sources you must have the consent of the persons concerned.
According to the Harvard system, the oral sources should not be in the list of references, but in a footnote on the pages where they are mentioned.
In the text you write:
In the footnote you write:
Ring 0520 - 22 34 10 eller maila firstname.lastname@example.org
Chatta med en bibliotekarie - vi svarar mellan kl. 10-17 alla helgfria vardagar under vår- och hösttermin.
Phone 0520 - 22 34 10 or e-mail email@example.com
Chat with a librarian - we are avaliable weekdays between 10 -17 o'clock during spring and autumn semester.