References
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- Hutchinson , G. E. 1957 . A treatise on Limnology , I John Wiley and Sons, New York. 1015 pp
- King , L. C. and King , L. A. 1959 . A reappraisal of the Natal Monocline . S. Afr. geogr. J. , 41 : 15 – 30 .