清代学者俞正燮查阅过许多明朝海上贸易和外交方面的档案，他所著的《癸巳类稿》对明朝若干项贡品的数量有明确的考证。

Yu Zhengxie had access to and read many Ming documents relating to maritime trade and diplomacy; his Guisi Leigao sheds light on the quantity of some tribute items presented.