1970CY/T 2-1999 Guidelines for Quality Evaluation and Grading of Printed Products
1991CY 2-1991 Appraising and grading quality for the printed matter of book and periodical
CY 2-1991 Appraising and grading quality for the printed matter of book and periodical was changed to CY/T 2-1999 Guidelines for Quality Evaluation and Grading of Printed Products.