Tian, Na, Sun, Jun, Xu, Wenbo and Lai, Choi-Hong ORCID: 0000-0002-7558-6398 (2011) An improved quantum-behaved particle swarm optimization with perturbation operator and its application in estimating groundwater contaminant source. Inverse Problems in Science and Engineering, 19 (2). pp. 181-202. ISSN 1741-5977 (Print), 1741-5985 (Online) (doi:https://doi.org/10.1080/17415977.2010.531470)