Before revision:  Recently, many studies indicated that the minimum spanning tree (MST) network whose metric distance is de?ned by using correlation coe?cients have strong implications on extracting infor- mation from return time series.
After revision:  Recently, many studies have shown the usefulness of minimal spanning trees (MST) network whose metric distance is de?ned by using correlation coe?cients have strong implications on extracting infor- mation from return time series.