1. El-Arishi, S. (2005) A conditional variance characterization of some discrete probability distributions, Statist. Papers, 46, 31–45.
2. Abu-Youssef, S.E. (2004) Nonparametric test for monotone variance residual life class of life distributions with hypothesis testing applications, Applied Mathematics and Computations, 158, 817–826.
3. Abu-Youssef, S.E. (2007) Testing decreasing (increasing) variance residual class of life distributions using kernel method, Applied Mathematical Sciences, 1, 1915–1927.
4. Abu-Youssef, S.E. (2009) A Goodness of fit approach to monotone variance residual life class of life distributions, Applied Mathematical Sciences, 3,15,715–724.
5. Al-Zahrani, B. and Stoyanov, J. (2008) On some properties of life distributions with increasing elasticity and log-concavity, Applied Mathematical Sciences, 2, 48, 2349–2361.