NRR definitions

Nrr

1) National research register
Found on https://www.crosswordclues.com/clue/nrr

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NRR

National Research Register
Found on http://www.encyclo.co.uk/local/20895

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NRR

Neuro retinal rim
Found on http://www.translationdirectory.com/glossaries/glossary140.htm

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