RT Journal T1 Characterizations of rings relative to an ideal A1 WANG Yong-duo, HE Jian PB JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE) FD 2017-08-20 YR 2017 JF JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE) JO JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE) VO 52 IS 8 SP 81 DO 10.6040/j.issn.1671-9352.0.2016.432 K1 semiregular ring;semiperfect ring;pseudo semiprojective module;projectivity class LK {http://lxbwk.njournal.sdu.edu.cn/EN/article/article_2900.shtml}