Determination keys for important West-European woods and tropical commercial timbers : with the help of a hand-lens or a light microscope / R.W. den Outer, W.L.H. van Veenendaal and Chr. VersteeghDeterminatietabel voor enige houtsoorten uit de gematigde zone naar anatomische kenmerken / door R.W. den Outer en Chr. VersteeghHistological investigations of the secondary phloem of Gymnosperms / R. W. den OuterBark anatomy of some Sarcolaenaceae and Rhopalocarpaceae and their systematic position / R.W. den Outer and A.P. VoorenWood anatomy of some Sarcolaenaceae and Rhopalocarpaceae and their systematic position / R.W. den Outer and P.R. SchützHistological investigations of the secondary phloem of Gymnosperms / Robert Willem den OuterTentative determination key to 600 trees, shrubs and climbers from the Ivory Coast, Africa, mainly based on characters of the living bark, besides the rhytidome and the leaf / R.W. den Outer