United States of America : : The National Gallery of Art (Washington) ; a twenty-five year report.

MLA

Mellon, Paul, and John Walker. United States of America : The National Gallery of Art (washington) ; a Twenty-five Year Report. Washington: National Gallery of Art (Washington), 1966.

APA

Mellon, P., & Walker, J. (1966). United States of America : The National Gallery of Art (Washington) ; a twenty-five year report. Washington: National Gallery of Art (Washington).

Chicago

Mellon, Paul, and John Walker. United States of America: The National Gallery of Art (washington) ; a Twenty-Five Year Report. Washington: National Gallery of Art (Washington), 1966.