"when we are referring to" vs. "when we refer to" uses the following sentence to give the source of a reference.
From English Grammar Today on Cambridge Dictionary
I found a lot of posts say it the same way, without any articles before the name "English Grammar Today".
I guess it's because "English Grammar Today" is kind of book name.
We don’t usually use articles with individual mountains or lakes when the name includes Mount or Lake: Mount Fuji, Lake Victoria. We don’t use articles with continents (Asia), countries (Romania), towns (Edinburgh), and streets (Lombard Street).
could be expanded as
... We don’t usually use articles with book names when the books are used as a reference.
is my understanding correct?