1.     Anthony L. Michaud, Aaron L. Frank, Donal J. Douglas, and XianZhen Zhao, "Ion excitation in a linear ion trap with a substantially quadrupole field having an added hexapole or higher order field", US Patent Application 2006/0118716, published June 08, 2006.

2.       X. Zhao, V. L. Ryjkov and H. A. Schuessler, "On the fluorescence profiles of laser cooled  Mg+ ions in a linear rf ion trap", Phys. Rev. A73, Article 033412 (2006).

3.       V. L. Ryjkov, X. Zhao and H. A. Schuessler, "Sympathetic cooling of fullerene ions by laser-cooled Mg+ ions in a linear rf trap", Phys. Rev. A74, Article 023401 (2006).

4.       V. L. Ryjkov, X. Zhao and H. A. Schuessler, "Simulations of the rf heating rates in a linear quadrupole ion trap", Phys. Rev. A73, Article 033414 (2005).

5.       X. Zhao, V. L. Ryjkov and H.A. Schuessler, "Parametric excitations of trapped ions in a linear rf ion trap", Phys. Rev. A66(6), Article 063414 (2002).

6.    X. Zhao, "Laser and mass spectroscopy in a linear rf quadrupole ion trap", Ph.D. Dissertation, Texas A&M University, 2001.

7.     Nikolai Konenkov, Donald J. Douglas, and XianZhen Zhao, "Method of operating quadrupoles with added multipole fields to provide mass analysis  in islands of stability", US provisional patent application filed on Feb 07, 2006.

8.   Edward S. Fry, George W. Kattawar, Deric J. Gray, XianZhen Zhao, and Zheng Lu, "Apparatus and method for direct measurement of  absorption and scattering coefficients", US Patent 7,057,730, June 06, 2006.

9.       A. L. Michaud, A. J. Frank, C. Ding, XianZhen Zhao, and D. J. Douglas, "Ion Excitation in a Linear Quadrupole Ion Trap with an Added Octopole Field",  J. Am. Soc. Mass Spectrom. 16, 835-849 (2005).