| Clue | Source | Date |
|---|---|---|
| Lumen per square meter, pl. | ||
| Illumination measures | Newsday | 19 Aug 2018 |
| Units of illumination | Universal | 07 Aug 2018 |
| Units of illumination | ||
| Illumination units | LA Times Daily | 15 Nov 2016 |
| Meter-candles | ||
| Illumination units | ||
| Units of illumination | ||
| Units of illumination | ||
| Units of illumination. |