AfDB, (2010), Domestic Resource Mobilization for Poverty Reduction in East Africa: South Africa Case Study, Regional Department East A (AREA), African Development Bank Group, Tunis.
Dickey, D. A., Fuller, W. A., (1979). Distribution of the Estimators for Autoregressive Time Series with a Unit Root, Journal of the American Statistical Association, Vol. 74, pp. 427-431.
Dickey, D. A., Fuller, W. A., (1981), Likelihood Ratio Statistics for Autoregressive Time Series with a Unit Root, Econometrica, Vol. 49, no. 4, pp. 1057-1072.
Embaye, A. B., (2007), Essays on Tax Evation and Government Spending in Developing Countries, Economics Dissertations, Paper 31, Georgia State University.
Engle, R. F., Granger, C. W. J., (1987), Cointegration and Error Correction: Representation, Estimation, and Testing, Econometrica, Vol. 55, pp. 251-276.
Jayasinghe, M., (2007), Pakistan: A Preliminary Evaluation of the Tax Gap, Department of Economics, Andrew Young School of Policy Studies, Georgia State University.
Lacko, M., (1999), Hidden Economy an Unknown Quantity? Comparative Analyses of Hidden economies in Transition Countries in 1989-95, Working Paper 9905, Department of Economics, University of Linz, Austria.
Mazhar, U., Pierre-Guillaume, M., (2011), The Shadow Economy as a Cause of Taxes and Inflation, Public Choice Society Papers, 2012, avialabe online at: www.pubchoicesoc.org/papers_2012/Meon_Mazhar.pdf.
Palil, M. R., Mustapha, A. F., (2011), The Evolution and Concept of Tax Compliance in Asia and Europe, Australian Journal of Basic and Applied Sciences, Vol. 5, no. 11, pp. 557-563.
Salar, L., Zaman K., Khilji B. A, Khan M. M., Lodhi M. S. (2013), The Consequences of Revenue Gap in Pakistan: Unveiling the Reality, Economic Modelling, Vol. 30, no. 1, pp. 281-294.
Siddiqi, M. W., Ilyas, M., (2011), Impact of Revenue Gap on Budget Deficit, Debt Deficit, Debt Burden and Economic Growth: Evidence from Pakistan, International Journal of Human and Social Sciences, Vol. 6, no. 2, pp. 89-98.
Sookram, S., Watson, P.K., (2005), Tax Evasion and the Hidden Economy in Trinidad and Tobago, available online at: http://sta.uwi.edu/salises/temp/Tax%20Evasion%20of%20the%20Hidden%20Economy%20-%20S%20Sookram.pdf.