The Penguin Classics. London: Penguin Books, 1951-1960
“Work for Penguin Books came in steadly. The Penguin Classics series was launched in 1946, until 1963 the covers were ornamented with 'roundels' matching the texts. Elizabeth Friedlander, from 1951 to 1960, designed several of these.”
Pauline Paucker. New borders: the working life of Elizabeth Friedlander. Oldham: Incline Press, 1998 (p. 45)
“Tschichold recruited and commissioned artists for all the series who drew their illustrations directly onto transparent film, litho plates, and for photographic reproduction by either photo-lito, photogravure, and letterpress. For the Penguin Classics, each book was individually distinguished by the roundel medallion design on each cover. These round decorative elements originated from coins in Roman times. Artists who have designed these roundels for the Penguin Classics include John Diebel, Cecil Keeling, Andrea Lee, William Grimmond, Elizabeth Friedlander, and Berthold Wolpe.”
Richard B. Doubleday. Jan Tschichold: the Penguin years. New Castle: Oak Knoll Press, 2006 (p. 131)