"Specifies an event that may occur multiple times. Timing schedules are used for specifying when events are expected or requested to occur, and may also be used to represent a schedule that was followed for past events. A Timing schedule can be a list of events and/or criteria for when the event happens, which can be expressed in a structured form and/or as a code. When both event and a repeating specification are provided, the list of events should be understood as an interpretation of the information in the repeat structure." - HL7 FHIR, Timing