diff --git a/polytope/solvers.py b/polytope/solvers.py
index 189a0d3..08142b0 100644
--- a/polytope/solvers.py
+++ b/polytope/solvers.py
@@ -10,6 +10,12 @@
 You can change this default at runtime by setting the variable
 `default_solver` in the module `solvers`.
 
+Nonfree (i.e., having restrictive licenses) solvers are also
+supported but require extra packages:
+
+* Gurobi, https://pypi.org/project/gurobipy/
+* MOSEK, https://pypi.org/project/Mosek/
+
 For example:
 
 ```python