中国科学院数学与系统科学研究院期刊网
An Erdös-Ko-Rado Theorem for Restricted Signed Sets
Yu-shuang Li
Acta Mathematicae Applicatae Sinica(English Series) . 2010, (1): 107 -112 .  DOI: 10.1007/s10255-009-6184-z