Consider a question asking "Is this documented in any citable reference?" (or similar)
It sort of feels like an (off topic) recommendation question, but also not really.
So, can I get a definitive answer as to whether the above, asked as is, is off topic?
Well, not as is 'as is', but 'as is'-ish - "this" obviously needs to be defined.
The question: Average time complexity of finding top-k elements
I realize that, depending on exactly what OP wants, it should be easy enough to modify to avoid asking for a citable reference (thus I figured a comment would be more appropriate than a close vote).
I'd like to reiterate - I don't think the above question necessarily needs to be closed (perhaps just modified a little), I'm just asking about this so I know and have something to reference.
Why this may be off topic:
There could be a tendency to posting answers that consists of little more than a link or reference, and we don't like that. Although one can certainly, in most cases, extract sufficient information from the paper, but the question isn't whether one can, but rather whether most users will (I don't think the typical Stack Overflow user will).
I'd like to point out the "they tend to" in the recommendation reason. As I understand it, we don't disallow them because all of them are unwanted, just because there's a tendency of bad things happening.
Also, it's very much a research-based question, not "a specific programming problem". So perhaps another site, but not really Stack Overflow (perhaps CS Theory, but I really have no idea about that).
Why this may be appropriate:
There shouldn't really be a tendency to "attracted opinionated answers or spam", as the recommendation reason says. But that doesn't mean another reason or a custom reason may not apply.