an Entity references as follows:
The hasBaseQualifier together with the hasNextQualfiier property allows qualifier characteristics to be combined and ordered. For example, for an MinimumDailyAverage qualifier, the hasBaseQualifier refers to Minimum and the hasNextQualifier refers to a DailyAverage qualifier, and for a DailyAverage qualifier, the hasBaseQualifier refers to a Daily qualifier and the hasNextQualifier refers to an Average qualifier.