Wanfang Database provides the author's paper title for journal article retrieval. The symbol in the middle indicates the type of document you cited. 1. M - monograph (including historical and historical treatises in ancient books); 2. C - collection of papers; 3

, N——Newspaper article; 4. J——Journal article; 5. D——Dissertation; 6. R——Research report; 7. S——Standard; 8. P——Patent.