Ludwig, E. (1931). Gifts of life: A retrospect. London: G. P. Putnam's Sons.
Trích dẫn kiểu ChicagoLudwig, Emil. Gifts of Life: A Retrospect. London: G. P. Putnam's Sons, 1931.
MLA CitationLudwig, Emil. Gifts of Life: A Retrospect. London: G. P. Putnam's Sons, 1931.
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