--- a/main/control/devel/pdfdoc/control.tex	Wed Sep 26 17:47:56 2012 +0000
+++ b/main/control/devel/pdfdoc/control.tex	Thu Sep 27 03:47:22 2012 +0000
@@ -90,11 +90,12 @@
 
 @sp 5
 @subheading Using the help function
-Some functions of the control package are listed with a leading @code{@@lti/}.
-This is only needed to view the help text of the function, e.g. @w{@code{help norm}}
-shows the built-in function while @w{@code{help @@lti/norm}} shows the overloaded
-function for @acronym{LTI} systems. Note that there are @acronym{LTI} functions
-like @code{pole} that have no built-in equivalent.
+Some functions of the control package are listed with the somewhat cryptic prefixes
+@code{@@lti/} or @code{@@iddata/}. These prefixes are only needed to view the help
+text of the function, e.g. @w{@code{help norm}} shows the built-in function while
+@w{@code{help @@lti/norm}} shows the overloaded function for @acronym{LTI} systems.
+Note that there are @acronym{LTI} functions like @code{pole} that have no built-in
+equivalent. The same is true for @acronym{IDDATA} functions like @code{nkshift}.
 
 When just using the function, the leading @code{@@lti/} must @strong{not} be typed.
 Octave selects the right function automatically. So one can type @w{@code{norm (sys, inf)}}

--- a/main/control/inst/arx.m	Wed Sep 26 17:47:56 2012 +0000
+++ b/main/control/inst/arx.m	Thu Sep 27 03:47:22 2012 +0000
@@ -88,9 +88,8 @@
 ##
 ## @strong{References}@*
 ## [1] Ljung, L. (1999)
-## System Identification - Theory for the User
-## Second Edition
-## Prentice Hall, New Jersey.
+## @cite{System Identification: Theory for the User: Second Edition}.
+## Prentice Hall, New Jersey, USA.
 ##
 ## @end deftypefn