This invention provides helper-dependent adenovirus cloning vectors and helper adenoviruses, and methods for making and using such preparations, wherein the helper adenoviruses contain recombinase target sites that are useful in reducing the level of contamination of helper virus in helper-dependent adenovirus vector preparations. A financial institution that issues the merchant card to a merchant acts as both issuer and acquirer for the merchant. The retention attribute indicates how long the electronic file should be retained.