This author has not been identified. Look up 'L. R. Van den Doel' in GoogleThis author has not been identified. It may be one of the following persons: Look up 'Lucas J. van Vliet' in GoogleThis author has not been identified. Look up 'K. T. Hjelt' in GoogleThis author has not been identified. Look up 'M. J. Vellekoop' in GoogleThis author has not been identified. Look up 'Ian T. Young' in GoogleThis author has not been identified. Look up 'F. Gromball' in GoogleThis author has not been identified. Look up 'Jan G. Korvink' in Google