William A. Spencer, "Factors of Significance in the Respiratory System", Annals of the New York Academy of Sciences66:4:891-930 (April 1957) doi:10.1111/j.1749-6632.1957.tb40777.x "The data on which this concept is based were obtained by experimental ablation of the brainstem in dogs and by pharmacological "dissection" of the patterning of respiration with morphine and dl-Dromoran."
