diff --git a/am_radius-opt/Rskp.m b/am_radius-opt/Rskp.m
index 1000ff9..bdb0b4b 100644
--- a/am_radius-opt/Rskp.m
+++ b/am_radius-opt/Rskp.m
@@ -2,7 +2,7 @@
 % function [R,gamma]=Rskp(s,k,p)
 %
 % Finds the optimal contractive k-step, s-stage GLM with order of accuracy p
-% for linear problems
+% for linear problems.
 %
 % Inputs:
 %       * s = # of stages
diff --git a/doc/RKtools.rst b/doc/RKtools.rst
index df963eb..17fe8ff 100644
--- a/doc/RKtools.rst
+++ b/doc/RKtools.rst
@@ -5,6 +5,13 @@ RKtools
 =======
 Some general utilities for analyzing Runge-Kutta methods.
 
+Some of the routines expect as input a structured array `rk`.
+This structure must have the fields `A, b, c`, containing its
+Butcher coefficients.  Optionally, it may represent an additive
+Runge-Kutta method or an embedded pair in which case it should also have
+`Ahat`, `bhat`, `chat` containing the coefficients of the secondary
+method.
+
 
 
 .. contents::
diff --git a/doc/am_radius-opt.rst b/doc/am_radius-opt.rst
index bae4cc7..f356cd8 100644
--- a/doc/am_radius-opt.rst
+++ b/doc/am_radius-opt.rst
@@ -52,11 +52,11 @@ Rkp
 
 Find the optimal SSP k-step explicit LMM with order of accuracy p.
 
-Inputs: 
+Inputs:
       * k = # of steps
       * p = order of accuracy
 
-Outputs: 
+Outputs:
       * R = the SSP coefficient
       * alpha, beta = the coefficients of the method
 
@@ -90,15 +90,16 @@ Rskp
 
 
 Finds the optimal contractive k-step, s-stage GLM with order of accuracy p
-for linear problems
+for linear problems.
 
-Inputs: s = # of stages
-        k = # of steps
-        p = order of accuracy
+Inputs:
+      * s = # of stages
+      * k = # of steps
+      * p = order of accuracy
 
-Outputs: 
-       R = threshold factor
-       gamma = coefficients of the polynomials
+Outputs:
+      * R = threshold factor
+      * gamma = coefficients of the polynomials
         
        for k=1, the resulting polynomial is
        `\sum_{j=0}^m (1+z/R)^j`
@@ -119,11 +120,11 @@ Rkp_dw
 Finds the optimal SSP k-step explicit LMM with order of accuracy p
 allowing downwind operators
 
-Inputs: 
+Inputs:
       * k = # of steps
       * p = order of accuracy
 
-Outputs: 
+Outputs:
       * R = the SSP coefficient
       * alpha, beta, tbeta = the coefficients of the method
 
@@ -144,7 +145,7 @@ Rkp_imp
 
 Find the optimal SSP k-step implicit LMM with order of accuracy p
 
-Inputs: 
+Inputs:
       * k = # of steps
       * p = order of accuracy
 
@@ -166,11 +167,11 @@ Rkp_imp_dw
 Finds the optimal k-step implicit LMM with order of accuracy p
 allowing downwinding
 
-Inputs: 
+Inputs:
       * k = # of steps
       * p = order of accuracy
 
-Outputs: 
+Outputs:
       * R = the SSP coefficient
       * alpha, beta, tbeta = the coefficients of the method