Foraminifera of the Orinoco-Trinidad-Paria shelf / by C.W. Drooger and J.P.H. KaasschieterThe microfauna of the aquitanian-burdigalian of southwestern France / by C.W. Drooger, J.P.H. Kaasschieter, A.J. KeyPetroleum geology of the southeastern North Sea and the adjacent onshore areas (The Hague, 1982) / ed. by J.P.H. Kaasschieter & T.J.A. Reijers