For some reason, people sometimes have a proclivity to write dates like this: “February of 1990.”
This flummoxes me, because the correct way is actually easier: February 1990. And you’d never say “February of 1990” aloud, would you?
I mean, no one says, “Oh yes, I got that cat sweater during the Christmas of 2011.” Unless you’re working on your Abe Lincoln impression, maybe, trying to sound old-timey?
Perhaps it’s an effort to aggrandize your writing. Well, stop it! Stop it, I say! Leave “of” out of your dates. They’re happier that way.
November 2013. Done.
M.E. Kinkade 
When I still taught English I constantly struggled with kids writing “4th of November” instead of just 4 November. Of course, you probably use the American November 4th which just seems completely the wrong way around to me 😉
We Americans are backward folk, I tell you. Sorry that “th of” has infected English there, too!