The administrative law judge shall receive such relevant evidence as may be adduced at the hearing. Parties to the hearing are the provider and OWCP. Evidence shall be presented under oath, orally or in the form of written statements. The administrative law judge shall consider the notice and response, including all pertinent documents accompanying them, and may also consider any evidence which refers to the provider or to any claim with respect to which the provider has provided medical services, hospital services, or medical services and supplies, and such other evidence as the administrative law judge may determine to be necessary or useful in evaluating the matter.