Stereograms for the determination of plagioclase feldspars in random sections by W. Nieuwenkamp. Nieuwenkamp, W. Feldspar. QE391.F3 N5 1966 553.69 NIS "Sole distributers for the U.S.A. and Canada: American Elsevier Publishing Company ... New York." Amsterdam : Elsevier Publishing Cy., 1966. 1966. 1966 Text 32 p. with 8 supplementary plates. eng