The article didn’t mention it and I’m not sure either.
The House can issue resolution after resolution - but if there’s no enforcement mechanism (IOW, issuing an arrest warrant for Rosenstein), what good is it?
Is there an enforcement mechanism of any kind?
Contempt. There is probably some sort of notice requirement before they can file actual charges, hence the seven days.
Here is the procedure for a contempt charge. Note, it starts in committee, but requires a majority vote in the full Congress or Senate.
http://www.nbcnews.com/id/19693051/ns/politics/t/what-contempt-congress/#.WyF9NoopCf0