Dennis 2006,第583頁. Dennis, James M. Regionalism in Painting. Cayton, Andrew R. L.; Sisson, Richard; Zacher, Chris (编). The American Midwest: An Interpretive Encyclopedia. Indiana University Press: 583–584. 2006 [2021-08-13]. ISBN 978-0-2530-0349-2. (原始内容存档于2021-08-13).
Dennis 2006,第583頁. Dennis, James M. Regionalism in Painting. Cayton, Andrew R. L.; Sisson, Richard; Zacher, Chris (编). The American Midwest: An Interpretive Encyclopedia. Indiana University Press: 583–584. 2006 [2021-08-13]. ISBN 978-0-2530-0349-2. (原始内容存档于2021-08-13).