Esto, R. (1990). Book of riddles for students & professionals. R.E. Books Marketing.
Chicagoスタイル(17版)引用形式Esto, Rey. Book of Riddles for Students & Professionals. [S.l.]: R.E. Books Marketing, 1990.
MLA(9版)引用形式Esto, Rey. Book of Riddles for Students & Professionals. R.E. Books Marketing, 1990.
警告: この引用は必ずしも正確ではありません.