Citazione Stile APA (7a Edizione)

Esto, R. (1990). Book of riddles for students & professionals. R.E. Books Marketing.

Citazione stile Chigago Style (17a edizione)

Esto, Rey. Book of Riddles for Students & Professionals. [S.l.]: R.E. Books Marketing, 1990.

Citatione MLA (9a ed.)

Esto, Rey. Book of Riddles for Students & Professionals. R.E. Books Marketing, 1990.