Do not leave “chores” like proofreading and referencing “for later”. They are part of the activity of writing.
Over time, the writing moment should unfold in a familiar way. It will be different for different people, but it should always begin with the typing of the key sentence and end with a two-minute proofread. After about twenty minutes of writing, you should read the paragraph out loud. It should come off the page comfortably. You have the rest of the time to make it so.
Now, about those references. You have chosen something you know well to write about, and knowing something means understanding your basis for believing it. That means that you know also the references that are required to support your claims. Suppose you type out the key sentence and then give some thought to the difficulty it poses for your reader. Your reader, you decide, will find what you are saying hard to believe. So you offer a few sentences of supporting evidence. But where did you get that evidence? Perhaps from a book written by an authority on the subject. Well, that authority, i.e., the reference to that book, is simply part your knowledge of the subject. If you don’t know the reference you don’t really know the fact. Force yourself to work to that standard.
Remember that this does not require you remember everything you cite. It just means that the decision to write something has to include digging the relevant page out of your notes. You may not know in your head exactly what it says; but you should know how to easily find it. It will contain the information you need to cite the source in question.
At the end of your writing moment you should always have a well-formed paragraph of at least six sentences and at most two-hundred words. The sentences should be as grammatically correct as you know how to make them and should be, to the best of your ability, free of typos and misspellings. They should be properly sourced to references that you yourself find reliable. You want to have the ability to produce a chunk of good scholarly writing in 27 minutes, so you have to give yourself the task of doing everything within the time allotted. Don’t rely on some additional process to make your prose even just adequate, passable. Aim to write well every time.
Of course, there will always be a need for a final proofreading of the whole document and for you to meticulously check each individual reference for accuracy. But you will find that these final tasks are much less of a chore if you did the actual work of writing carefully and conscientiously in the first place.