diff --git a/lib/KorAP/XML/TEI/Tokenizer/Aggressive.pm b/lib/KorAP/XML/TEI/Tokenizer/Aggressive.pm
index 5099eeb..c36b605 100644
--- a/lib/KorAP/XML/TEI/Tokenizer/Aggressive.pm
+++ b/lib/KorAP/XML/TEI/Tokenizer/Aggressive.pm
@@ -37,7 +37,7 @@
     };
   };
 
-  return;
+  return $self;
 };
 
 
diff --git a/lib/KorAP/XML/TEI/Tokenizer/Conservative.pm b/lib/KorAP/XML/TEI/Tokenizer/Conservative.pm
index 0efb648..237d87f 100644
--- a/lib/KorAP/XML/TEI/Tokenizer/Conservative.pm
+++ b/lib/KorAP/XML/TEI/Tokenizer/Conservative.pm
@@ -32,7 +32,7 @@
     $self->_add_surroundings($txt, $-[3], $+[3]) if $3;
   };
 
-  return
+  return $self;
 };
 
 
diff --git a/lib/KorAP/XML/TEI/Tokenizer/External.pm b/lib/KorAP/XML/TEI/Tokenizer/External.pm
index 7b740a1..4fe3751 100644
--- a/lib/KorAP/XML/TEI/Tokenizer/External.pm
+++ b/lib/KorAP/XML/TEI/Tokenizer/External.pm
@@ -58,6 +58,7 @@
   return unless $self->{pid};
   my $out = $self->{chld_in};
   print $out $txt . $self->{sep};
+  return $self;
 };
 
 
diff --git a/script/tei2korapxml b/script/tei2korapxml
index 3875200..318051a 100755
--- a/script/tei2korapxml
+++ b/script/tei2korapxml
@@ -317,16 +317,32 @@
         #
 
 
+        # ~ tokenization ~
+
         if ( $_GEN_TOK_EXT ){
 
-          $ext_tok->tokenize($data);
+          $ext_tok->tokenize($data)->to_zip(
+            $zipper->new_stream("$_root_dir$dir/$_tok_dir/$_tok_file_ext"),
+            $text_id_esc
+          );
 
         }
 
         if ( $_GEN_TOK_INT ){
 
-          $cons_tok->tokenize($data);
-          $aggr_tok->tokenize($data);
+          # Tokenize and output
+          $cons_tok->tokenize($data)->to_zip(
+            $zipper->new_stream("$_root_dir$dir/$_tok_dir/$_tok_file_con"),
+            $text_id_esc
+          );
+
+          $aggr_tok->tokenize($data)->to_zip(
+            $zipper->new_stream("$_root_dir$dir/$_tok_dir/$_tok_file_agg"),
+            $text_id_esc
+          );
+
+          $aggr_tok->reset;
+          $cons_tok->reset;
         }
 
         $data = encode_utf8( $data );
@@ -348,33 +364,6 @@
 
         write_tokens() if $_TOKENS_PROC && @tokens;
 
-
-        # ~ tokenization ~
-
-        if ( $_GEN_TOK_EXT ) {
-
-          $ext_tok->to_zip(
-            $zipper->new_stream("$_root_dir$dir/$_tok_dir/$_tok_file_ext"),
-            $text_id_esc
-          )
-
-        }
-
-        if ( $_GEN_TOK_INT ){
-
-          # Output token streams to zip streams
-          $cons_tok->to_zip(
-            $zipper->new_stream("$_root_dir$dir/$_tok_dir/$_tok_file_con"),
-            $text_id_esc
-          );
-          $aggr_tok->to_zip(
-            $zipper->new_stream("$_root_dir$dir/$_tok_dir/$_tok_file_agg"),
-            $text_id_esc
-          );
-          $aggr_tok->reset;
-          $cons_tok->reset;
-        }
-
         #print STDERR "$0: write_tokenization(): DONE\n";
 
         $data_fl = 0; $buf_in = $data = $dir = ""; # reinit.
diff --git a/t/tokenization.t b/t/tokenization.t
index b132a63..92b7cc3 100644
--- a/t/tokenization.t
+++ b/t/tokenization.t
@@ -24,6 +24,12 @@
 $aggr->reset->tokenize("Der alte bzw. der grau-melierte Mann");
 is_deeply($aggr, [0,3,4,8,9,12,12,13,14,17,18,22,22,23,23,31,32,36]);
 
+like(
+  $aggr->reset->tokenize("Der")->to_string('a'),
+  qr!id="t_0"!,
+  'Chainable'
+);
+
 # Test conservative
 my $cons = KorAP::XML::TEI::Tokenizer::Conservative->new;
 $cons->tokenize("Der alte Mann");