The phrase "with reference to" typically indicates a connection or relation between two or more things. There are several synonyms that can be used in place of this phrase to provide greater variety and interest to your writing. Some possible options include "regarding," "concerning," "pertaining to," "in relation to," "about," and "as for." Each of these alternatives conveys the same basic meaning, but may emphasize different aspects or nuances of the relationship being discussed. By using a variety of synonyms, you can add depth and complexity to your writing and avoid repeating the same phrases over and over.