in reference to
US /ɪn ˈref.ər.əns tuː/
UK /ɪn ˈref.ər.əns tuː/

1.
in riferimento a, riguardo a
concerning or regarding something; in relation to
:
•
I am writing in reference to your recent inquiry.
Scrivo in riferimento a la vostra recente richiesta.
•
His comments were made in reference to the new policy.
I suoi commenti sono stati fatti in riferimento alla nuova politica.