APA (7th ed.) Citation

Erdős Pál. (1940). An extremum-problem concerning trigonometric polynomials.

Chicago Style (17th ed.) Citation

Erdős Pál. An Extremum-problem Concerning Trigonometric Polynomials. 1940.

MLA (8th ed.) Citation

Erdős Pál. An Extremum-problem Concerning Trigonometric Polynomials. 1940.

Warning: These citations may not always be 100% accurate.