University of Chicago
Encyclopedia Romana: Roman Calendar the Fasti Antiates
This site from the Encyclopedia Romana includes a picture of a reconstruction of the Fasti Antiates, along with an explanation of the calendar and its lettering. The information is not too in-depth, but informative and factual. A great...
Wolfram Research
Wolfram Science World: The Julian Calendar
This site from Science World under Wolfram Research contains brief information about the Julian Calendar. The information is factual and interesting, and it also contains links for further information on the subjects.