[LONGITUDINAL]
input = {V, Cl}

EQUATION:
C = pkmodel(V, Cl)

;--------------------------------------------
[INDIVIDUAL]  ; variability levels = {id, occ}
input = {V_pop, o_V0, o_V1, Cl_pop, o_Cl0}

DEFINITION:
V  = {distribution=logNormal, reference=V_pop,  varlevel={id,id*occ}, sd= {o_V0,o_V1}}
Cl = {distribution=logNormal, reference=Cl_pop, varlevel=id, sd= o_Cl0}
