Cita APA (7a ed.)

HARPER, W., & HARPER, W. (1976). Statistics W.m. Harper. Macdonald and Evans.

Cita Chicago Style (17a ed.)

HARPER, W.M, y W.M HARPER. Statistics W.m. Harper. Macdonald and Evans, 1976.

Cita MLA (8a ed.)

HARPER, W.M, y W.M HARPER. Statistics W.m. Harper. Macdonald and Evans, 1976.