You can't use a string as a reference while strict refs is in use. That's the whole point of strict refs. If you want to use a string as a reference, you should disable strict refs.

no strict 'refs';
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Your question is a bit like asking, "I've put up a sign on my front gate which says 'No Dogs Allowed'. Now I can't let my dog into my garden. How do I let my dog into my garden?"

If you want to use non-strict references, don't put up a sign (use strict) that says only strict references are allowed.