Speck, J. (1991). Comte, Mill, James, Peirce, Dewey, Mach. Vandenhoeck & Ruprecht.
Cita Chicago (17th ed.)Speck, Joseph. Comte, Mill, James, Peirce, Dewey, Mach. Göttingen: Vandenhoeck & Ruprecht, 1991.
Cita MLA (8th ed.)Speck, Joseph. Comte, Mill, James, Peirce, Dewey, Mach. Vandenhoeck & Ruprecht, 1991.
Atenció: Aquestes cites poden no estar 100% correctes.