Thanks, I'm learning something here.
I remember looking for "a dozen of" vs "a dozen" while translating.
Looks like both are used, but what you said seems more correct --> "of" is not required.
But check this out, it's interesting:
- http://public.wsu.edu/~brians/errors/dozenof.html
- http://forum.wordreference.com/showthread.php?t=372795
hmmmm, so basically it's:
1) A dozen (stuffs) --> Correct
2) Dozens of (stuffs) --> Correct
3) A dozen of (stuffs) --> Wrong
But I'd still like to have a definite answer on that matter.