MODERN PHYSICS LETTERS B, vol. 24, no. 10, page. 979 - 994, 2010-04-20
PHYSICS LETTERS A, vol. 374, no. 41, page. 4231 - 4237, 2010-09-13
APPLIED MATHEMATICS AND COMPUTATION, vol. 215, no. 6, page. 2035 - 2044, 2009-11-15
PHYSICS LETTERS A, vol. 374, no. 10, page. 1218 - 1227, 2010-02-22