James A. Field, Leon C. Marshall and Chester W. Wright. Materials For the Study of Elementary Economics https://archive.org/stream/materialsforstud00mars#page/n5/mode/2up, University of Chicago Press, 1913. Preface
Leon Carroll Marshall was an American economist, Professor of Political Economy and fourth dean of the Booth School of Business from 1909 to 1924, Professor at the Law School of the Johns Hopkins University, and Professor at the American University. He is known for his works on our economic organization, business administration, curriculum-making in the social studies and the divorce court. Wikipedia
James A. Field, Leon C. Marshall and Chester W. Wright. Materials For the Study of Elementary Economics https://archive.org/stream/materialsforstud00mars#page/n5/mode/2up, University of Chicago Press, 1913. Preface