1. 1) Peters A, Palay SL and Webster H.deF. The Neuroglial Cells. In: The Fine Structure of the Nervous System: the Nervous and Their Supporting Cells, 3thed, New York, Oxford University Press, 1991; 273-295.
2. 2) Wolff JR and Bär Th. Developmental and adult variations of the pericapillary glial sheath in the cortex of rat. In: J. Cervós-Navarro et al., eds, The Cerebral Vessel Wall, New York, Raven Press, 1976; 7-13.
3. 3) Sasaki H and Mannen H. Morphological analysis of astrocytes in the bullfrog (Rana catesbeiana) spinal cord with special reference to the site of attachment of their processes. J Comp Neurol 1981 May 1; 198(1):13-35.
4. 4) Tsujiyama Y. Appendix: the method for staining neuroglial cells. In:Tsujiyama Y,eds, Neurogila:Its Approaches to the Brain Function, Tokyo. Igaku Shoin Ltd. 1977; 210-211 (in Japanese).
5. 5) Stensaas LJ and Stensaas SS. Astrocytic neuroglial cells, oligodendrocytes and microgliacytes in the spinal cord of the toad. II. Electron microscopy. Z Zellforsch Mikrosk Anat 1968; 86(2): 184-213.