Petrarca, A. E., & Lay, W. M. (1969). The double-KWIC coordinate index: A new approach for preparation of high-quality printed indexes by automatic indexing techniques. Computer and Information Science Research Center, Ohio State University.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Petrarca, Anthony E., و William Michael Lay. The Double-KWIC Coordinate Index: A New Approach for Preparation of High-quality Printed Indexes by Automatic Indexing Techniques. Columbus, Ohio: Computer and Information Science Research Center, Ohio State University, 1969.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Petrarca, Anthony E., و William Michael Lay. The Double-KWIC Coordinate Index: A New Approach for Preparation of High-quality Printed Indexes by Automatic Indexing Techniques. Computer and Information Science Research Center, Ohio State University, 1969.