H. T. Eid, “Factors Influencing the Determination of Shale Classification Indices and Their Correlation to Mechanical Properties,” Geotechnical and Geological Engineering, Vol. 24, No. 6, 2005, pp. 1695-1713. doi:10.1007/s10706-005-5726-2
 S. K. Vanapalli, D. G. Fredlund, D. E. Pufahl and A. W. Clifton, “Model for the Prediction of Shear Strength with Respect to Soil Suction,” Canadian Geotechnical Journal, Vol. 33, No. 3, 1996, pp. 379-392. doi:10.1139/t96-060
 D.G. Freudlund, S. K. Vanapalli and D. E. Pufahl, “The Relationship between the Soil-Water Characteristic Curve and the Shear Strength of a Compacted Glacial Till,” Geotechnical Testing Journal, Vol. 19, No. 3, 1996, pp. 259-268. doi:10.1520/GTJ10351J
 A. Oberg and G. Salfours, “Determination of Shear Strength Parameters of Unsaturated Silts and Sands Based on the Water Retention Curve,” Geotechnical Testing Journal, Vol. 20, No. 1, 1997, pp. 40-48. doi:10.1520/GTJ11419J
 N. Khalili and M. H. Khabbaz, “A Unique Relationship for x for the Determination of the Shear Strength of Unsaturated Soils,” Geotechnique, Vol. 48, No. 5, 1997, pp. 681-687. doi:10.1680/geot.1918.104.22.1681
 M. Abramento and C. S. Carvalho, “Geotechnical Parameters for the Study of Natural Slope Instabilization at Serra do Mar-Brazilian Southeast,” Proceeding of the 12th International Conference on Soil Mechanics and Foundation Engineering, Rio de Janeiro, Vol. 3, 1990, pp. 1599-1602.
 T. M. P. De Campos and C. W. Carillo, “Direct Shear Testing on Unsaturated soils from Rio de Janerio,” Proceeding of the 1st International conference on an unsaturated soil, Paris, 6-8 September 1995, pp. 31-38.
 V. Escario and J. F. T. Jucá, “Strength and Deformation of Partially Saturated Soils,” Proceedings of the 12th International Conference on Soil Mechanics and Foundation Engineering, Rio de Janeiro, Vol. 2, 1989, pp. 43-46.
 Z. Shen and S. Yu, “The Problems in the Present Studies on Mechanics of Unsaturated Soils,” Proceedings of the Symposium on Geotechnical Aspects of Regional Soils, Atomic Energy Press, Beijing, 1996.
 A. Kaya and K. P. Kwong, “Evaluation of Common Practice Empirical Procedures for Residual Friction Angle of Soils: Hawaiian Amorphous Materials Rich Colluvial Soil Case Study,” Engineering Geology, Vol. 92, No. 1-2, 2007. doi:10.1016/j.enggeo.2007.03.002
 W. G. Harris, L. W. Zelazny, J. C. Parker, J. C. Baker, R. S. Weber and J. H. Elder, “Engineering Properties of Soils as Related to Mineralogical and Particle-Size Variables,” Soil Science Society of America Journal, Vol. 48, 1984, pp. 978-982. doi:10.2136/sssaj1984.03615995004800050005x
 G. Tsiambaos, “Correlation of Mineralogy and Index Properties with Residual Strength of Iraklion Marls,” Engineering Geology, Vol. 30, No. 3-4, 1991, pp. 357-369. doi:10.1016/0013-7952(91)90068-V
 A. Tugrul and I. H. Zarif, “The Influence of Mineralogi- cal Textural and Chemical Characteristics on the Durability of Selected Sandstone in Istanbul, Turkey,” Bulletin of Engineering Geology and the Environment, Vol. 57, No. 2, 1998, pp. 185-190. doi:10.1007/s100640050034
 D. Schwertfeger and W. Hendershot, “Determination of Effective Cation Exchange Capacity and Exchange Acidity by a One-Step BaCl2 Method,” Soil Science Society of America, Vol. 73, No. 2, 2009, pp. 737-743. doi:10.2136/sssaj2008.0009
 S. K. Vanapalli, “A Simple Technique for Determining the Shear Strength of Fine-Grained Unsaturated Soils us- ing the Conventional Direct Shear Apparatus,” 2nd Canadian Specialty Conference on Computer Applications in Geotechnique, Winnipeg, 28-30 April 2002, pp. 245-253.
 R. T. Odell, T. H. Thornburn and L. J. Mckenzie, “Relationships of Atterberg Limits to Some Other Properties of Illinois Soils,” Soil Science Society of America Proceedings, Vol. 24, No. 4, 1960, pp. 297-300. doi:10.2136/sssaj1960.03615995002400040025x
 C. A. Seybold, A. E. Moustafa and J. E. Robert, “Linear Regression Models to Estimate Soil Liquid Limit and Plasticity Index From Basic Soil Properties,” Soil Science, Vol. 173, No. 1, 2008, pp. 25-34. doi:10.1097/ss.0b013e318159a5e1
 V. Khanithi and C. Khanhai, “Breaking Frontiers and Barriers in Engineering,” 4th LACCEI International Latin American and Caribbean Conference for Engineering and Technology (LACCET’2006), Puerto Rico, 21-23 June 2006.
 W. Haines, “Studies in the Physical Properties of Soils: I. Mechanical Properties Concerned in Cultivation,” The Journal of Agricultural Science, Vol. 15, No. 2, 1925, pp. 178-200. doi:10.1017/S0021859600005669