I upvoted your post above, but still your regex m/(\b(?:[A-Z]+(?:\s+[A-Z]+)*)+\b)/g made me squirm. Whenever I see sequences of nested quantifiers like that:+)*)+ I get uncomfortable, remembering various pathelogical cases I've constructed in the past.

To that end, I thunk again, and came up with this which I believe meets the 'spec', whilst avoiding the nested quantifiers;

m[
 (
    \b
    [A-Z]
    (?: [A-Z\s]* [A-Z] )? 
    \b
 )
]gx
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