diff --git a/doc/Section_howto.txt b/doc/Section_howto.txt
index c252a39a14..6774e4a4f6 100644
--- a/doc/Section_howto.txt
+++ b/doc/Section_howto.txt
@@ -2005,9 +2005,9 @@ formalism.
 
 6.21 Calculating viscosity :link(howto_21),h4
 
-The shear viscosity eta of a fluid can be measured in at least 4 ways
+The shear viscosity eta of a fluid can be measured in at least 5 ways
 using various options in LAMMPS.  See the examples/VISCOSITY directory
-for scripts that implement the 4 methods discussed here for a simple
+for scripts that implement the 5 methods discussed here for a simple
 Lennard-Jones fluid model.  Also, see "this
 section"_Section_howto.html#howto_20 of the manual for an analogous
 discussion for thermal conductivity.
@@ -2055,7 +2055,7 @@ See the "fix viscosity"_fix_viscosity.html command for details.
 
 The fourth method is based on the Green-Kubo (GK) formula which
 relates the ensemble average of the auto-correlation of the
-stress/pressure tensor to eta.  This can be done in a steady-state
+stress/pressure tensor to eta.  This can be done in a fully
 equilibrated simulation which is in contrast to the two preceding
 non-equilibrium methods, where momentum flows continuously through the
 simulation box.
@@ -2122,6 +2122,13 @@ variable     v equal (v_v11+v_v22+v_v33)/3.0
 variable     ndens equal count(all)/vol
 print        "average viscosity: $v \[Pa.s/] @ $T K, $\{ndens\} /A^3" :pre
 
+The fifth method is related to the above Green-Kubo method,
+but uses the Einstein formulation, analogous to the Einstein
+mean-square-displacement formulation for self-diffusivity. The
+time-integrated momentum fluxes play the role of Cartesian
+coordinates, whose mean-square displacement increases linearly
+with time at sufficiently long times. 
+
 :line
 
 6.22 Calculating a diffusion coefficient :link(howto_22),h4