-the same language, but type-safe with a \gls{GADT}\footnote{\glspl{GADT} are
-not supported in the current version of \gls{Clean} and therefore the syntax is
-artificial. However, \glspl{GADT} can be simulated using bimaps}. Unfortunately
-the lack of extendability stays a problem. If a language construct is added no
+the same language, but type-safe with a \gls{GADT}. \glspl{GADT} are not
+supported in the current version of \gls{Clean} and therefore the syntax is
+artificial. However, it has been shown that \glspl{GADT} can be simulated using
+bimaps or projection pairs\cite{cheney_lightweight_2002}. Unfortunately the
+lack of extendability stays a problem. If a language construct is added no