| Rank | Abbreviation | Meaning |
|---|
| ***** | NL. | Navigation Ltd
| |
| ***** | NL. | NIL No Limit
| |
| ***** | NL. | Nonantum Library (Newton, MA)
| |
| ***** | NL. | Northeast Library (Minneapolis, MN)
| |
| **** | NL. | Nitrogen Laser
| |
| **** | NL. | Northwest Library (Charlotte, NC)
| |
| **** | NL. | Naples Library (Naples, NY)
| |
| **** | NL. | Northwood Library (Baltimore, MD)
| |
| **** | NL. | Natasha Lynn
| |
| **** | NL. | normal liver
| |
| **** | NL. | children with normal language
| |
| **** | NL. | Napoleon Library (New Orleans, LA)
| |
| **** | NL. | normal subjects
| |
| *** | NL. | Norfork Library (Norfork, CT)
| |
| *** | NL. | Navasota Library (Navasota, TX)
| |
| *** | NL. | Navy Lightered
| |
| *** | NL. | Necrobiosis lipoidica
| |
| *** | NL. | Northland Library (Alpena, MI)
| |
| *** | NL. | Navy Laboratories
| |
| *** | NL. | nasal lavage
| |
| *** | NL. | Norwood Library (Knoxville, TN)
| |
| *** | NL. | National Lakeshore
| |
| *** | NL. | Nute Library (Milton, NH)
| |
| *** | NL. | neural lobe
| |
| ** | NL. | Nesmith Library (Windham, NH)
| |