The authors employ the ‘dartboard approach’ pioneered by Ellison and Glaeser to analyze the spatial concentration of New Economy employment in Germany, the coagglomeration of firms belonging to different sub-sectors of Neuer Markt and the
(intraregional) spillovers between different high tech industries.
Link
http://www.ersa.org/ersaconfs/ersa03/cdrom/papers/230.pdf