APA (7e ed.) Bronvermelding

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

Chicago (17e ed.) Bronvermelding

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

MLA (9e ed.) Bronvermelding

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