Cita APA (7th ed.)

Elderton, W. P., & Johnson, N. L. (1969). Systems of frequency curves. Cambridge University.

Cita Chicago (17th ed.)

Elderton, William Palin, i Norman Lloyd Johnson. Systems of Frequency Curves. Cambridge: Cambridge University, 1969.

Cita MLA (9th ed.)

Elderton, William Palin, i Norman Lloyd Johnson. Systems of Frequency Curves. Cambridge University, 1969.