Adisak Sangsongfa. (2000) Development of the tools to defing formal specification of requirements using the VDM case study of borrow-return the book in the library system. Mahidol University,:ม.ป.ท.Adisak Sangsongfa. 2000. Development of the tools to defing formal specification of requirements using the VDM case study of borrow-return the book in the library system. ม.ป.ท.:Mahidol University,;Adisak Sangsongfa. Development of the tools to defing formal specification of requirements using the VDM case study of borrow-return the book in the library system. ม.ป.ท.:Mahidol University, 2000. Print.