The American Heritage® Dictionary of the English Language: Fourth Edition. 2000.
Appendix I
Indo-European Roots
ENTRY:
(s)mer-1
DEFINITION:
To remember. 1. Suffixed zero-grade form *m-no-.mourn, from Old English murnan, to mourn, from Germanic *murnan, to remember sorrowfully. 2. Reduplicated form *me-mor-.a.Mimir, from Old Norse Mimir, a giant who guards the well of wisdom, from Germanic *mi-mer-;b.memorable, memorandum, memory; commemorate, remember, from Latin memor, mindful. (Pokorny (s)mer- 969.)
-no-. mourn, from Old English murnan, to mourn, from Germanic *murnan, to remember sorrowfully. 2. Reduplicated form *me-mor-. a. Mimir, from Old Norse Mimir, a giant who guards the well of wisdom, from Germanic *mi-mer-; b. memorable, memorandum, memory; commemorate, remember, from Latin memor, mindful. (Pokorny (s)mer- 969.) 
