Update README.md

README.md

@@ -83,7 +83,8 @@ function calc_control(y,r)
     u  = G1f(e)
 end
 ```
-`G1` and `G4` must here be represented by [`StateSpace`](http://juliacontrol.github.io/ControlSystems.jl/latest/lib/constructors/#ControlSystems.ss) types from [`ControlSystems.jl`](https://github.com/JuliaControl/ControlSystems.jl).
+`G1` and `G4` must here be represented by [`StateSpace`](http://juliacontrol.github.io/ControlSystems.jl/latest/lib/constructors/#ControlSystems.ss) types
+from [`ControlSystems.jl`](https://github.com/JuliaControl/ControlSystems.jl), e.g., `G1 = ss(A,B,C,D)`.
 `TransferFunction` types can easily be converted to a `StateSpace` by `Gss = ss(Gtf)`.
 Continuous time systems can be discretized using `Gd = c2d(Gc, h)[1]`. (The sample time of a process is available through `h = sampletime(P)`.)