... The 2014 Impact Factor is 2.757 according to the Thomson Reuters Journal Citation Reports ... references see: a [38-43]; b [41,42]; c [43]; d [44]; e [38-43,45-47]; f [38-43,48,49]; g [49,50]; h [51]; i [52]; j [53]; k ... A considerable improvement of this method was developed by Clark et al. ...