In particular, some upper bounds of the vertex arboricity of the integer distance graph G(Z, D) are obtained when D is a set of positive integers and Z the set of all integers.
特别地，当D是某正整数集合，Z是整数集时，得出了整数距离图G（Z ，D）的点荫度的几个上界。
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Xu W. -D. , Chen G. , Zhang D. -H. A porous tantalum uncemented acetabular cup in acetabular revision arthroplasty.