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

1.
关于, 提及
concerning or regarding something; in relation to
:
•
I am writing in reference to your recent inquiry.
我写信是关于您最近的询问。
•
His comments were made in reference to the new policy.
他的评论是关于新政策的。