DOE:10.3171/jns.1975.42.2.0166
DOE:10.3171/jns.1978.49.1.0013
DOE:10.3171/jns.1982.57.2.0219
DOE:10.3171/jns.1983.58.6.0857
DOE:10.3171/jns.1984.60.4.0737
DOE:10.3171/jns.1986.64.2.0243
DOE:10.3171/jns.1988.69.6.0830
DOE:10.3171/jns.1989.70.4.0573
DOE:10.3171/jns.1990.73.2.0254
DOE:10.3171/jns.2003.98.1.0032