Cita APA (7th ed.)
Hays, S. P. (1999). Conservation and the gospel of efficiency: The progressive conservation movement, 1890-1920. University of Pittsburgh Press.
Cita Chicago (17th ed.)
Hays, Samuel P. Conservation and the Gospel of Efficiency: The Progressive Conservation Movement, 1890-1920. Pittsburgh, Pennsylvania: University of Pittsburgh Press, 1999.
Cita MLA (9th ed.)
Hays, Samuel P. Conservation and the Gospel of Efficiency: The Progressive Conservation Movement, 1890-1920. University of Pittsburgh Press, 1999.
Atenció: Aquestes cites poden no estar 100% correctes.