"Source Document" means the original records containing the key details of a transaction, including its date, purpose, and amount. Source documents provide documentary evidence or proof that a transaction occurred and are critical to verify and support the information provided on a tax return. Typical source documents include, but are not limited to, wage and tax statements, sales invoices, purchase invoices, canceled checks, deposit slips, and point-of-sale records, such as cash register tapes.
35 Miss. Code. R. 1-01-230