The forth part is classified into two parts . the first one analyses the legal effects to the parties the second one studies the legal effects to the third party . the final part is about retention of title and risk of loss 主要研究了标的物处分与第三人的关系,标的物处分与第三人的关系,标的物上设定动产质押;抵押时与所有权保留竟合时法律关系以及所有权保留与强制执行的关系及问题。