Whether and to what extent deductions shall be allowed depends upon specific legislative Acts, and only where there is a clear provision can any particular deduction be allowed. Therefore, a deduction will be allowed only if the taxpayer can establish the validity and correctness of such a deduction. 77Am. Jur. 2d State and Local Taxation, subsection 518 (1973).
This rule is intended to implement Iowa Code sections 42235. and 42261..
Iowa Admin. Code r. 701-57.4