Iowa Code § 214A.5: Documentation.

1. A wholesale dealer or retail dealer shall, when making a sale of motor fuel, give to a purchaser upon demand a sales slip.

2. A wholesale dealer selling ethanol blended gasoline, biobutanol blended gasoline, or biodiesel blended fuel to a purchaser shall provide the purchaser with a statement indicating its classification as provided in section 214A.2. The statement may be on the sales slip provided in this section or a similar document, including but not limited to a bill of lading or invoice.