9E. P. Kearsleya, P. J. Wainwrightb. Ash content for optimum strength of foamed concrete. Cement and Concrete Research, 2002, (32):241-246.
10E. P. Kearsleva, P. J. Wainwrightb. The effect of high fly ash content on the compressive strength of foamed concrete. Cement and Concrete Research, 2001, (31): 105 - 112.