Citazione APA

Elton, E., & Gruber, M. (1979). Port folio theory 25 years after. North holland publishing company.

Stile di citazione Chicago

Elton, E.J, e M.J Gruber. Port Folio Theory 25 Years After. New York: North holland publishing company, 1979.

Citazione MLA

Elton, E.J, e M.J Gruber. Port Folio Theory 25 Years After. North holland publishing company, 1979.