^ Chase 2003:31 : "the earliest surviving formulas for gunpowder can be found in the Wujing zongyao, a military work from around 1040"
^ Chase 2003:31 : "ti kasapaan a kadagiti nabati a pormula para iti polbora ket mabirukan idiay Wujing zongyao, ti obra ti militar manipud idi agarup a 1040"