I have a date and want to know in what period this is.

Reference ranges:
period begin end
jan 1/1/2008 14/1/2008
feb 15/1/2008 14/2/2008
mrt 15/2/2008 14/3/2008
apr 15/3/2008 14/4/2008

test value: result:
12/3/2008 mrt
1/4/2008 apr

I can do this with an nested IF function, but then I´m limited to 6 nested
IF statements. And I need more, in this case 7 or 8.

Is there some case statement like worksheet function ?