L.L. Ma, S.G. Chu, H.X. Cheng and X.B. Xu*, Polycyclic aromatic hydrocarbons in subsurface soils…. Geoderma, 2005, 129, 100-210

L.L. Ma, S.G. Chu, X.T. Wang, H.X. Cheng, X.F. Liu and X.B. Xu*, Polycyclic aromatic hydrocarbons in the surface soils… Chemosphere, 2005, 58(10), 1355-1363

L.L. Ma, D. Muir, X. T. Wang and X.B. Xu*, Simultaneous analysis of organic pollutants in soils by gas chromatography/gas chromatography-mass spectrometry. Int. J. Environ. Anal. Chem,. 2005, 85(2) 89-98

L.L. Ma, S.G. Chu and X.B. Xu*, Phthalate residues in greenhouse soil from Beijing suburbs… Bull. Environ. Contam. Toxicol., 2003, 71(2): 394-399

L.L. Ma, S.G. Chu and X.B. Xu*, Organic contamination in the greenhouse soils… J. E nviron.Monit., 2003, 5: 786-790

X.H. Li, L.L. Ma, X.F. Liu, S. Fu, H.X. Chen and X.B. Xu*, Distribution of organochlorine pesticides in urban soil… Bull. Environ. Contam. Toxicol., 2005, 74: 938-945

X.T. Wang, S.G. Chu, L.L. Ma, Y.Z. Sun, X.H. Li and X.B. Xu*, Contamination of priority polycyclic aromatic hydrocarbons in water from Guanting reservoir and the Yongding river. Bull. Environ. Contam. Toxicol., 2004, 72: 194-201

S.G. Chu, H. Liu, L.L. Ma and X.B. Xu*, Polycylic aromatic hydrocarbons in soil adjacent to highways in Beijing... Bull. Environ. Contam. Toxicol., 2003, 70: 972-977

X.H. Li, X.B. Xu*, X.T. Wang and L.L. Ma, Headspace single-drop microextraction with gas chromatography for determination of volatile halocarbons in water samples. Int. J. Environ. Anal. Chem., 2004, 84(9): 633-645

X.H. Li, S.G. Chu, S. Fu, L.L. Ma, X.F. Liu and X.B. Xu*, Off-line concentration of bisphenol A and three alkylphenols by SPE then on-line concentration and rapid separation by reverse-migration micellar electrokinetic chromatography. Chromatographia, 2005, 61:161-166