Do you need to actually know that it is a citation or can you just use the 'period space (' as your trigger? Are there cases where this pattern doesn't involve a citation?

For instance, you could do a wildcard search and replace to move the period which precedes an open bracket by searching for
.{space}(\(*\))

and replacing it with
{space}\1.

Note that the {space} should be an actual space.

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Andrew Lockton
Chrysalis Design, Melbourne Australia