APA (7th ed.) Citation

Sierpiński, W. (1970). 250 problems in elementary number theory. Elsevier.

Chicago Style (17th ed.) Citation

Sierpiński, Wacław. 250 Problems in Elementary Number Theory. New York ; Inc: Elsevier, 1970.

MLA (9th ed.) Citation

Sierpiński, Wacław. 250 Problems in Elementary Number Theory. Elsevier, 1970.