关于非自动衡器的国家技术规范，主要包括国标的各类衡器的技术规范，尤其JJG539-97、JJG648和JJG564，网上比较难得免费下载点
On non-automatic weighing instrument of national technical specifications, including National technical specifications of various scales, in particular JJG539-97, JJG648 and JJG564, relatively rare free download online at (2008-08-29, Others, 24391KB, 下载6次)