The following year the scholar Basil Gray published his article in the British Museum Quarterly which argued that Ripa had been commissioned by the emperor Kang Xi to go to Jehol and make the engravings.
隔年一位英國學者克雷在大英季刊上發表文章，考證當年馬國賢供職清廷，為康熙派往熱河協助雕版。