4Xuefeng W,Jie R,Youguo W.Co-inventor analysis on China' s international technology collab- oration in US patent activities: 1976-2010 [J].Procedia Engineering, 2012, (37) : 314-322.
5Secar M.Statistic analysis of international tourism on romanian seaside [J].Annals of the Universi- ty of Petrosani Economics, 2010,10(01 ) : 327-334.
6Zabolotnov Y M,Nikonova I A.Disturbance ranging in capsule atmosphere descent [J].Russian Aeronautics ( Iz VUZ ), 2010,53 ( 04 ) : 375-381.
