diff --git a/nix/agda.nix b/nix/agda.nix
index 5b51061..41a4eb2 100644
--- a/nix/agda.nix
+++ b/nix/agda.nix
@@ -96,7 +96,7 @@ let
 
 in
 {
-  inherit agdaStdlib agdaStdlibClasses agdaStdlibMeta ;
+  inherit agdaStdlib agdaStdlibClasses agdaStdlibMeta agdaSets agdaIOGPrelude ;
   agdaWithDeps = agdaWithPkgs deps;
   leiosSpec = leiosSpec;
 }
diff --git a/nix/shell.nix b/nix/shell.nix
index aaeacbe..a541a3a 100644
--- a/nix/shell.nix
+++ b/nix/shell.nix
@@ -27,7 +27,8 @@ in
   env.AGDA_STDLIB = "${agda.agdaStdlib}/standard-library.agda-lib";
   env.AGDA_STDLIB_CLASSES = "${agda.agdaStdlibClasses}/standard-library-classes.agda-lib";
   env.AGDA_STDLIB_META = "${agda.agdaStdlibMeta}/standard-library-meta.agda-lib";
-  env.FORMAL_LEDGER_LIB = "${agda.formalLedger}/formal-ledger.agda-lib";
+  env.AGDA_SETS = "${agda.agdaSets}/abstract-set-theory.agda-lib";
+  env.AGDA_IOG_PRELUDE = "${agda.agdaIOGPrelude}/iog-prelude.agda-lib";
 
 # prompt = "[ouroboros-leios]$ ";
 
@@ -38,7 +39,8 @@ in
     ${agda.agdaStdlib}/standard-library.agda-lib
     ${agda.agdaStdlibClasses}/standard-library-classes.agda-lib
     ${agda.agdaStdlibMeta}/standard-library-meta.agda-lib
-    ${agda.formalLedger}/formal-ledger.agda-lib
+    ${agda.agdaSets}/abstract-set-theory.agda-lib
+    ${agda.agdaIOGPrelude}/iog-prelude.agda-lib
 
   Run 'emacs' to edit .agda files.
   '';