APA

Hopkins D. P., . (1948). Chemicals, humus, and the soil : a simple presentation of contemporary knowledge and opinions about fertilizers, manures, and soil fertility. New York: Chemical publishing.

Chicago

Hopkins Donald P, . 1948. Chemicals, humus, and the soil : a simple presentation of contemporary knowledge and opinions about fertilizers, manures, and soil fertility. New York: Chemical publishing.

Harvard

Hopkins D. P., . (1948). Chemicals, humus, and the soil : a simple presentation of contemporary knowledge and opinions about fertilizers, manures, and soil fertility. New York: Chemical publishing.

MLA

Hopkins Donald P, . Chemicals, humus, and the soil : a simple presentation of contemporary knowledge and opinions about fertilizers, manures, and soil fertility. New York: Chemical publishing. 1948.