1. Structural Geology;Billings,1982
2. Possible late Palaeozoic glaciation in the central parts of the Yemen Arab Republic;El-Nakhal;J. Glaciol.,1984
3. A lithostratigraphic subdivision of Kohlan Group in Yemen Arab Republic;El-Nakhal;Iraqi J. Sci.,1985
4. Principles of Physical Geology;Holmes,1983
5. Mechanics of thermal contraction cracks and ice-wedge polygons in permafrost;Lachenbruch;Geol. Soc. Am., Special Paper 70,1962