“…As a result, this treatment conforms to incorporating the form of singularity thoroughly. Examples of such treatment can be found in different studies (Chen et al, 2010;Li et al, 1987Li et al, , 2004Li et al, , 2006Li et al, , 2007Lu et al, 2004;Lu and Li, 2005;Poullikkas et al, 1998;Xanthis et al, 1981).…”