MLA

Van Soelen, Theodore, 1890-1964, artist. Cowboys' day off : a reproduction of an original painting by Theodore Van Soelen, presented by California Gold Label Beer. [between 1950 and 1960]. https://collections.library.yale.edu/catalog/2016183.

APA, 6th edition

Van Soelen, Theodore, 1890-1964, artist. ([between 1950 and 1960])[Cowboys' day off : a reproduction of an original painting by Theodore Van Soelen, presented by California Gold Label Beer]. https://collections.library.yale.edu/catalog/2016183.