History

Time	Change
2013-07-20 07:40:09+00:00	Created
2013-07-20 07:40:09+00:00	Associated with GB 12050
2013-07-20 07:40:09+00:00	Associated with GB 12050-1989
2013-07-20 07:40:09+00:00	Associated with GB 12050-89
2020-10-10 05:36:47+00:00	Associated with GB/T 12050
2020-10-10 05:36:47+00:00	Associated with GB/T 12050-1989