-

This way you get to avoid repeating "month", e.g.

"Subd. 4. Failure to use or sell for intended purpose;
report required. (a) Any person who buys aviation gasoline or
special fuel for aircraft use and who has paid the excise taxes
due directly or indirectly through the amount of the tax being
included in the price, or otherwise, and uses said gasoline or
special fuel in motor vehicles or knowingly sells it to any
person for use in motor vehicles shall, *on or before the 23rd
day of the month following that in which* such gasoline or
special fuel was so used or sold..."
http://www.revisor.leg.state.mn.us/stats/296A/15.html

--------------------------------------------------
Note added at 8 mins (2006-06-13 08:12:20 GMT)
--------------------------------------------------

*were*, in fact, rather than "are" since they will have been provided already by then!!

IMO