1. Lapp, H., u. A. Nolte: Vergleichende elektronenmikroskopische Untersuchungen am Mark der Rattenniere bei Harnkonzentrierung und Harnverdünnung. Frankfurt. Z. Path. 71, 617?633 (1962).
2. Muehrcke, R.C., S. Rosen, and F.I. Volini: The interstitial cells of the renal papilla: Light and electronmicroscopic studies. 2d Internat. Symposium on Pyelonephritis, Boston, June 5th an 6th, 1964 (to be published).
3. Reynolds, E.S.: The use of lead citrate at high pH as an electron-opaque stain in electron microscopy. J. Cell Biol. 17, 208?212 (1963).
4. Rhodin, J.A.G.: Renal Disease, ed. by D.A.K. Black, p. 149. Oxford: Blackwell. Sci. Publ. 1962.
5. ? An atlas of ultrastructure, p. 101. Philadelphia and London: W.B. Saunders Co. 1963.