Is it standard practice to make sure that multiple, numbered citations occuring together are ordered? If including multiple, numbered citations together, is it standard practice^ to order them according to number? For example, one might see

Several studies [1,3,5] show that quantity X is relevant to Y.


Or 

Several studies [1][3][5] show that quantity X is relevant to Y.


It is also common to see 

Several studies [5,1,3] show that quantity X is relevant to Y.


The last is easy to achieve if using a tool such as bibtex, with a bibliography ordered in some way other than order of mention in the text.

Is there any authoritative reference that such ordering is preferable in general? To clarify, since this question was marked off-topic, the issue is whether, in the absence of guidelines from a journal, etc. there is any sufficiently-authorative concept of general style here. If the answer is "no" (which I believe it is), that is acceptable. If the answer is "yes," it can be defended with references to general academic style guides.



^as far as this can be determined across fields. I'm personally interested in mathematics, computer science, computational science, physics, and related fields.
In my experience, there is no particular necessity or requirement to ensure that numbered citations go in order.  Certainly, I have never personally encountered an instance with an IEEE or ACM publication (which use numerical order) where the publisher actually cared if this was the case.

That said, it certainly is much tidier to order the citations in a set, and doing so is very simple to do, so I often will do so if I notice they are out of order.

That said, there is one case in which I will not order the citations, and that is if a citation cluster has some citations that are more important than others.  In that case, I will always keep the citations ordered in decreasing importance instead, just to make it a little more likely for the reader to figure out which is the most important one.