Let's say I'm describing what some person is currently doing, and I say:
He is reading articles which he is summarizing in his blog.
Is this sentence (and specifically, this usage of "which") correct?
Do I need a comma before it? Or do I need "that" instead?
(I know I can reword it into something else entirely, like changing the order into "He is summarizing the articles that he is reading in his blog" or something else, but that's not what I'm asking about here.)
Addendum from OP's comment: I have used the progressive tense because what I want to say that he is reading several articles and summarizing them at the same time as he is reading them. Also, I am not describing a habit, nor something in the future, but what is happening currently.