diff --git a/src/Pure/Thy/bibtex.ML b/src/Pure/Thy/bibtex.ML
--- a/src/Pure/Thy/bibtex.ML
+++ b/src/Pure/Thy/bibtex.ML
@@ -1,64 +1,64 @@
 (*  Title:      Pure/Thy/bibtex.ML
     Author:     Makarius
 
 BibTeX support.
 *)
 
 signature BIBTEX =
 sig
   val check_database:
     Position.T -> string -> (string * Position.T) list * (string * Position.T) list
   val check_database_output: Position.T -> string -> unit
   val cite_macro: string Config.T
 end;
 
 structure Bibtex: BIBTEX =
 struct
 
 (* check database *)
 
 type message = string * Position.T;
 
 fun check_database pos0 database =
   \<^scala>\<open>bibtex_check_database\<close> database
   |> YXML.parse_body
   |> let open XML.Decode in pair (list (pair string properties)) (list (pair string properties)) end
   |> (apply2 o map o apsnd) (fn pos => Position.of_properties (pos @ Position.get_props pos0));
 
 fun check_database_output pos0 database =
   let val (errors, warnings) = check_database pos0 database in
     errors |> List.app (fn (msg, pos) =>
       Output.error_message ("Bibtex error" ^ Position.here pos ^ ":\n  " ^ msg));
     warnings |> List.app (fn (msg, pos) =>
       warning ("Bibtex warning" ^ Position.here pos ^ ":\n  " ^ msg))
   end;
 
 
 (* document antiquotations *)
 
 val cite_macro = Attrib.setup_config_string \<^binding>\<open>cite_macro\<close> (K "cite");
 
 val _ =
   Theory.setup
    (Document_Antiquotation.setup_option \<^binding>\<open>cite_macro\<close> (Config.put cite_macro) #>
     Thy_Output.antiquotation_raw \<^binding>\<open>cite\<close>
       (Scan.lift
         (Scan.option (Parse.verbatim || Parse.cartouche) -- Parse.and_list1 Args.name_position))
       (fn ctxt => fn (opt, citations) =>
         let
           val thy = Proof_Context.theory_of ctxt;
           val bibtex_entries = Resources.theory_bibtex_entries (Context.theory_long_name thy);
           val _ =
-            if null bibtex_entries andalso Context.theory_name thy <> Context.PureN then ()
+            if null bibtex_entries andalso Context.theory_long_name thy <> Context.PureN then ()
             else
               citations |> List.app (fn (name, pos) =>
                 if member (op =) bibtex_entries name then ()
                 else error ("Unknown Bibtex entry " ^ quote name ^ Position.here pos));
           val _ =
             Context_Position.reports ctxt
               (map (fn (name, pos) => (pos, Markup.citation name)) citations);
           val opt_arg = (case opt of NONE => "" | SOME s => "[" ^ s ^ "]");
           val arg = "{" ^ space_implode "," (map #1 citations) ^ "}";
         in Latex.string ("\\" ^ Config.get ctxt cite_macro ^ opt_arg ^ arg) end));
 
 end;