Atwater, R., Atwater, F., Kessel, E., & Lawson, R. (1949). Mr. Poppers Pinguine (11.-15. Tausend.). Alfred Holz Verlag.
Lua i Stíl Chicago (17ú heag.)Atwater, Richard, Florence Atwater, Elisabeth Kessel, agus Robert Lawson. Mr. Poppers Pinguine. 11.-15. Tausend. Berlin: Alfred Holz Verlag, 1949.
Lua MLA (8ú heag.)Atwater, Richard, et al. Mr. Poppers Pinguine. 11.-15. Tausend. Alfred Holz Verlag, 1949.
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