I need to write the below formuls to include all twelve months, and of course
I can't do more than 7 if's. Anyone have any ideas?

=IF(ISERROR(IF($D$5="APR07",MAR07!G14,IF($D$5="MAY 07",APR07!G$14,IF($D$5="JUN07",MAY07!G$14,"No
Data")))),"",IF($D$5="APR07",MAR07!G14,IF($D$5="MA Y07",APR07!G$14,IF($D$5="JUN07",MAY07!G$14,"No Data"))))