diff --git a/src/Tools.jl b/src/Tools.jl
index 3aa417db..04c2e9eb 100644
--- a/src/Tools.jl
+++ b/src/Tools.jl
@@ -72,7 +72,8 @@ function P0_to_I(P0, m)
 end
 
 function Pcr(ω, n0, n2)
-    1.8962*(2π*PhysData.c/ω)^2/(4π*n0*n2)
+    # G. Fibich and A. L. Gaeta, Optics Letters, 25, 5, 335, 2000, doi: 10.1364/OL.25.000335.
+    1.86225*(2π*PhysData.c/ω)^2/(4π*n0*n2)
 end
 
 paramfields = (:E, :τfw, :τ0, :ω, :λ, :material, :P, :T, :shape,:P0, :β2, :N0, :n0, :n2,