APA

Cooper W., Association for Computing Machinery & ACM Special Interest Group on Information Retrieval. (1981). Proceedings of the 4th annual international ACM SIGIR conference on Information storage and retrieval theoretical issues in information retrieval. New York, NY: ACM.

Chicago

Cooper William, Association for Computing Machinery and ACM Special Interest Group on Information Retrieval. 1981. Proceedings of the 4th annual international ACM SIGIR conference on Information storage and retrieval theoretical issues in information retrieval. New York, NY: ACM.

Harvard

Cooper W., Association for Computing Machinery and ACM Special Interest Group on Information Retrieval. (1981). Proceedings of the 4th annual international ACM SIGIR conference on Information storage and retrieval theoretical issues in information retrieval. New York, NY: ACM.

MLA

Cooper William, Association for Computing Machinery and ACM Special Interest Group on Information Retrieval. Proceedings of the 4th annual international ACM SIGIR conference on Information storage and retrieval theoretical issues in information retrieval. New York, NY: ACM. 1981.