@article {9959,
	title = {Theory of conserved spin current and its application to a two-dimensional hole gas},
	journal = {Physical Review B - Condensed Matter and Materials Physics},
	year = {2008},
	doi = {10.1103/PhysRevB.77.075304},
	author = {Ping Zhang and Zhigang Wang and Junren Shi and Di Xiao and Qian Niu}
}
