[with sth; see also: address, concern, consider, handle, take up, treat
To deal with Tf, we note that...... [= Regarding <Concerning> Tf, we note]
Although [1] deals mainly with the unit disc, most proofs are so constructed that they apply to more general situations.
It became clear that the Riemann integral should be replaced by some other type of integral, better suited for dealing with limit processes.
A survey of the research on fn(x,y) up to 1970 (most of it dealing with the case n=1) was given in [3].
This topic has been dealt with by many authors.