W. D. Tonkelaar

Gas chromatography versus infra-red spectrometry for determination of mineral oil dissolved in water

R. Jeltes, W.A.M. den Tonkelaar, R. Jeltes, 1972 .

Application of capillary gas chromatography in the analysis of hydrocarbons in the environment

R. Jeltes, E. Burghardt, T. Thijsse, 1977 .

Use of azure A instead of methylene blue for determination of anionic detergents in drinking and surface waters

G. Bergshoeff, W. D. Tonkelaar, 1969 .