Cite this article:

. . New Technology of Library and Information Service, 1994, 10(5): 50-52.

URL:

https://manu44.magtech.com.cn/Jwk_infotech_wk3/EN/10.11925/infotech.1003-3513.1994.05.10     OR     https://manu44.magtech.com.cn/Jwk_infotech_wk3/EN/Y1994/V10/I5/50