Tolong jelaskan mengenai Sumber dari Pierre Guillaume Frédéric le Play

Brooke, Michael Z. (1970). Le Play, Engineer and Social Scientist: The Life and Work of Frederic Le Play. Harlow UK: Longmans.

Herbertson, Fanny Louisa Dorothea (1950). The Life of Frédéric Le Play, Ledbury, Herefordshire: Le Play House Press.