"When scheduling a calendar entity@ such as an event@ it is a prerequisite that an organizer has the calendar address of each attendee that will be invited to the event. Additionally@ access to an attendee's current ""busy time"" provides an a priori indication of whether the attendee will be free to participate in the event. In order to meet these challenges@ a calendar user agent (CUA) needs a mechanism to locate (URI) individual user's calendar and free/busy time. This memo defines three mechanisms for obtaining a URI to a user's calendar and free/busy time. These include: - Manual transfer of the information; - Personal data exchange using the vCard format; and - Directory lookup using the LDAP protocol."