Contributions to the study of the problem-solving process.

MLA

John, E. Roy. Contributions to the study of the problem-solving process. [Washington] : [American Psychological Association], [1958]

APA

John, E. (1958). Contributions to the study of the problem-solving process. [Washington] : [American Psychological Association].

Chicago

John, E. Roy. Contributions to the study of the problem-solving process. [Washington] : [American Psychological Association], [1958]