# Old-style figures: Use in references/brackets (e.g. to equations, bibliography) or not?

In my documents I usually use old-style figures for "non-mathematical" numbers. By this I mean for example dates, page numbers, telephone numbers and the like. For tables, results of equations etc. I generally use lining figures, to distinguish them from the other numbers and to make it easier to recognize the magnitude. I usually do this with the \num{} command provided by siunitx.

Using OSF by default sometimes looks a bit odd, though. Consider for instance the case of putting an OSF between brackets for referencing. Here are two examples:

As you can see, lining figures nicely fill up the brackets, they seem to fit into them. The OSF (2) and (3) look odd though, for example there is a dissymmetry in the (3) because it stretches below the bracket and there is a space above it.

This is even more so the case with the [189] in the second example. The 9 even extents until below the bracket!

My specific question is now how to handle this case. Is what I have shown here fine? Should I use OSFs for my main text, but then lining figures in such brackets? If yes, would this not look inconsistent? Should I not use OSFs at all? Or is there another fix?

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