Els Valkenburg has written:
'Understanding multiple chemical sensitivity' -- subject(s): Multiple chemical sensitivity, Popular works
Paul I. Van Valkenburg has written: 'The Van Valkenburg family in America' -- subject(s): Genealogy
Els Kolff has written: 'De Tempel'
Nicholas Valkenburg has written: 'Occurrence of iron bacteria in ground-water supplies of Alabama' -- subject(s): Groundwater, Iron bacteria, Microbiology
Ton Valkenburg has written: 'Ere wie ere toekomt' 'Mensen in de ouderdom' -- subject(s): Social work with older people
Els Lagrou has written: 'A fluidez da forma'
Els Hupkes has written: 'De kleine Britt'
Els de Groen has written: 'Die Andere Seite der Strasse'
Els van Berlo has written: 'Mijn werkstijl, een manier van leven'
Els H. Swaab has written: 'Arob proces dossier' -- subject(s): Administrative procedure
Marc Masdeu has written: 'Els escalfadors'
Els van den Bent has written: 'Geschiedenis van Rotterdam' -- subject(s): History
Jaume Batiste has written: 'Els tres mosqueters'