MATERNAL AND CHILD HEALTH CARE OF CHINA, Volume 19, Issue 17,2004, Pages 14-14, doi:10.3969/j.issn.1001-4411.2004.17.006
CENTRAL PLAINS MEDICAL JOURNAL, Volume 31, Issue 17,2004, Pages 11, doi:10.3760/cma.j.issn.1674-4756.2004.17.009
JOURNAL OF PRACTICAL MEDICAL TECHNIQUES, Volume 11, Issue 17,2004, Pages 1691-1692, doi:10.3969/j.issn.1671-5098.2004.17.016