The article “Chemithermomechanical Pulp from Mixed High Density Hardwoods” (TAPPI, July 1988: 145–146)

reports on a study in which the accompanying data was obtained to relate y
specific surface area (cm3

/g) to x1
%

NaOH used as a pretreatment chemical and x2
treatment time (min) for a batch of pulp.