Hays, S. P. (1999). Conservation and the gospel of efficiency: The progressive conservation movement, 1890-1920. University of Pittsburgh Press.
Cóipeáladh chuig an ngearrthaisce go rathúil é
Níorbh fhéidir cóipeáil chuig an ngearrthaisce
Lua i Stíl Chicago (17ú heag.)
Hays, Samuel P. Conservation and the Gospel of Efficiency: The Progressive Conservation Movement, 1890-1920. Pittsburgh, Pennsylvania: University of Pittsburgh Press, 1999.
Cóipeáladh chuig an ngearrthaisce go rathúil é
Níorbh fhéidir cóipeáil chuig an ngearrthaisce
Lua MLA (9ú heag.)
Hays, Samuel P. Conservation and the Gospel of Efficiency: The Progressive Conservation Movement, 1890-1920. University of Pittsburgh Press, 1999.
Cóipeáladh chuig an ngearrthaisce go rathúil é
Níorbh fhéidir cóipeáil chuig an ngearrthaisce
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.