. . "Clinical Trials United States." . . "Voluntary Works United States." . . "Voluntary Workers United States." . . . . . "Volunteer patients and the NIH Clinical Center"@en . . . . . . . . . "Partners in research volunteer patients and the NIH Clinical Center"@en . . . . . . . . "Partners in research : volunteer patients and the NIH Clinical Center"@en . "Research United States." . . "Patients United States." . .