@article {1960,
	title = {Quantification of Linear Entropy for Quantum Entanglement in He, H- and Ps- Ions Using Highly-Correlated Hylleraas Functions},
	journal = {Few-Body Systems},
	volume = {54},
	year = {2013},
	pages = {2147-2153},
	author = {Chien-Hao Lin and Lin, Yen-Chang and Ho, Yew Kam}
}
