Deference to reference (7)
I believe the answer is:
respect
This clue is a double definition.
'deference' is the first definition.
(I know that deference can be written as respect)
'reference' is the second definition.
(I've seen this in another clue)
'to' acts as a link.
(Other definitions for respect that I've seen before include "Appreciate - courtesy" , "Comply with - deference" , "Treat with care, deference" , "value" , "Look up to" .)