in reference to

in reference to или with reference to или in regard to или with regard to  {prep.}

В связи с чем-л.; с точки зрения; в отношении чего-л.; относительно; о чем-л.

I am writing with reference to your last letter.

He spoke in reference to the Boy Scouts.

I spoke to him with regard to his low marks.

In regard to the test tomorrow, it is postponed.

Ср.: IN RELATION TO, IN RESPECT TO.