7Choi CY,Kim SB,Pak PK,et,al.Effect of N-acylation on structure and properties of chitosan fiber[J].Carb Poly,2007,68(3):122-127.
8Wu.,Zivanovic S.Determination of the degree of acetylation(DA)of chitin and chitosan by an improved first derivative UV method[J].Carb Poly,2008,73(2):248-253.