American Psychological Association 6th edition

Greenfield, L. E., & Greenfield, S. J. (n.d.). Some problems of combinatorial number theory related to Bertrand’s postulate.

ISO-690 (author-date, English)

GREENFIELD, Lawrence E. and GREENFIELD, Stephen J., [no date]. Some problems of combinatorial number theory related to Bertrand’s postulate. .

Modern Language Association 9th edition

Greenfield, L. E., and S. J. Greenfield. Some Problems of Combinatorial Number Theory Related to Bertrand’s Postulate.

Mohr Siebeck - Recht (Deutsch - Österreich)

Greenfield, Lawrence E./Greenfield, Stephen J.: Some problems of combinatorial number theory related to Bertrand’s postulate,

Emerald - Harvard

Greenfield, L.E. and Greenfield, S.J. (n.d.). “Some problems of combinatorial number theory related to Bertrand’s postulate”.

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