Philadelphia Museum of Art, Shoemaker, I. H., Helfand, W. H., & Ittmann, J. W. (2011). Health for sale: Posters from the William H. Helfand collection : interview with William H. Helfand. Philadelphia Museum of Art.
Lua i Stíl Chicago (17ú heag.)Philadelphia Museum of Art, Innis H. Shoemaker, William H. Helfand, agus John W. Ittmann. Health for Sale: Posters from the William H. Helfand Collection : Interview with William H. Helfand. Philadelphia, PA: Philadelphia Museum of Art, 2011.
Lua MLA (8ú heag.)Philadelphia Museum of Art, et al. Health for Sale: Posters from the William H. Helfand Collection : Interview with William H. Helfand. Philadelphia Museum of Art, 2011.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.