Nelson, J. L. (1977). Population and progress: Is there a conflict? (2ª ed.). Prentice Hall.
Cita Chicago (17th ed.)Nelson, Jack L. Population and Progress: Is There a Conflict? 2ª ed. Prentice Hall, 1977.
Cita MLA (9th ed.)Nelson, Jack L. Population and Progress: Is There a Conflict? 2ª ed. Prentice Hall, 1977.
Atenció: Aquestes cites poden no estar 100% correctes.