1. Karayannacos, P. E., Yahon, D., Vasko, J. S. Narrow lumbar spinal canal with “vascular” syndromes. Arch Surg. 1976; 111: 803–806.
2. Warren, R. Two kinds of intermittent cleudication. (Editorial) Arch Surg. 1976; 111: 739.
3. Goodreau, J. J., Creasy, J. K., Flanigan, P., Burnham, S. J., Kudra, J. C, Schafer, M. R, Bergan, J. J., Yao, S. T. Rational approach to the differentiation of vascular and neurogenic claudication. Surgery 1978; 84: 749–757.
4. Epstein, B. S., Epstein, J. A., Jones, M. D. Intermittent neurogenic claudication. Texas Med. 1977; 73: 53–60.
5. Snyder, E. N., Mulfinger, G. L., Lambert, R. W. Claudication caused by compression of the cauda equina. Am. J. Surg. 1975; 130: 172–5.