D(t):	creep compliance at time t (1/kPa).
GL:	gauge length in meters (mm).
Davg:	average diameter of all specimens (mm).
bavg:	average thickness of all specimens (mm).
Pavg:	average creep load (kN).
ΔXtm,t:	trimmed mean of the normalized horizontal deformations of all specimen faces at time t (mm/mm).
Ccmpl:	correction factor.
$\frac{X}{Y}$:	absolute value of the ratio of the normalized, trimmed mean of the horizontal deformations (i.e., ΔXtm,t) to the normalized, trimmed mean of the vertical deformations (i.e, ΔYtm,t) at a time corresponding to ½ the total creep test time for all specimen faces.