diff --git a/pitfall/pitfall/minimal-pdf-source.rkt b/pitfall/pitfall/minimal-pdf-source.rkt
index 869c7812..5d0a18eb 100644
--- a/pitfall/pitfall/minimal-pdf-source.rkt
+++ b/pitfall/pitfall/minimal-pdf-source.rkt
@@ -45,4 +45,5 @@
  0
  (co-stream
   (co-dict '#hasheq((Length . 55)))
-  #"  BT\n    /F1 18 Tf\n    0 0 Td\n    (Hello World) Tj\n  ET"))
\ No newline at end of file
+  #"  BT\n    /F1 18 Tf\n    0 0 Td\n    (Hello World) Tj\n  ET"))
+(co-trailer (co-dict (hasheq 'Size 5 'Root (co-io-ref 1 0))))
\ No newline at end of file
diff --git a/pitfall/pitfall/parser.rkt b/pitfall/pitfall/parser.rkt
index bf019b21..375d0ba8 100644
--- a/pitfall/pitfall/parser.rkt
+++ b/pitfall/pitfall/parser.rkt
@@ -1,6 +1,6 @@
 #lang brag
 
-pf-program : pf-header pf-body  pf-trailer
+pf-program : pf-header pf-body pf-trailer
 pf-header : PDF-HEADER
 @pf-body : pf-object*
 @pf-object : pf-null | CHAR | BOOLEAN | INT | REAL | pf-name | pf-string | pf-array | pf-dict | pf-stream | pf-indirect-object | pf-indirect-object-ref | pf-comment
diff --git a/pitfall/pitfall/render.rkt b/pitfall/pitfall/render.rkt
index efc84cfe..87794952 100644
--- a/pitfall/pitfall/render.rkt
+++ b/pitfall/pitfall/render.rkt
@@ -1,6 +1,6 @@
 #lang at-exp racket/base
 (require (for-syntax racket/base)
-         racket/string pitfall/struct br/define)
+         racket/string pitfall/struct br/define racket/bytes sugar/debug racket/format)
 (provide (all-defined-out)
          (all-from-out pitfall/struct)
          (except-out (all-from-out racket/base) #%module-begin))
@@ -9,47 +9,76 @@
   #'(#%module-begin (render-args . ARGS)))
 (provide (rename-out [mb #%module-begin]))
 
-(define (render-args . args)
-  (display
-   (string-append
+(define (make-xref-table locs)
+  (string->bytes/latin-1 @string-append{
+ xref
+ 0 @(number->string (length locs))
+ 0000000000 65535 f
+ @(let ([sep " 00000 n\n"])
     (string-join
-     (map cosexpr->string (append args (list "%%EOF")))
-     "\n\n"))))
+     (for/list ([loc (in-list (cdr (sort locs < #:key car)))])
+       (~r #:min-width 10 #:pad-string "0" (cdr loc))) sep #:after-last sep))
+ }))
+
+
+(define (render-args . args)
+  (define-values (bstrs offset locs)
+    (for/fold ([cobstrs null]
+               [offset 0]
+               [io-locs '((0 . 0))])
+              ([cosexpr (in-list args)])
+      (define cobstr (cosexpr->bytes cosexpr))
+      (values
+       (cons cobstr cobstrs)
+       (+ offset (bytes-length cobstr))
+       (if (co-io? cosexpr)
+           (cons (cons (co-io-idx cosexpr) offset) io-locs)
+           io-locs))))
+  (define trailer-str (car bstrs))
+  (define other-strs (cdr bstrs))
+  (define result (apply bytes-append `(,@(reverse other-strs) ,(make-xref-table locs) ,trailer-str #"\n%%EOF")))
+  (display result)
+  result)
   
-(define (cosexpr->string x)
-  (let loop ([x x])
-    (cond
-      [(co-version? x)
-       @string-append{%%PDF-@(number->string (co-version-num x))}]
-      [(co-header? x) (loop (co-header-string x))]
-      [(co-array? x)
-       @string-append{[ @(string-join (map loop (co-array-items x)) " ") ]}]
-      [(co-io? x)
-       @string-append{
-        @(loop (co-io-idx x)) @(loop (co-io-rev x)) obj
-        @(loop (co-io-thing x))
-        endobj}]
-      [(co-dict? x)
-       @string-append{
-        <<
-        @(string-join
-          (for/list ([(k v) (in-hash (co-dict-dict x))])
-            @string-append{@(loop k) @(loop v)}) "\n")
-        >>}]
-      [(co-io-ref? x)
-       @string-append{@(loop (co-io-ref-idx x)) @(loop (co-io-ref-rev x)) R}]
-      [(co-stream? x)
-       @string-append{
-        @(loop (co-stream-dict x))
-        stream
-        @(loop (co-stream-data x))
-        endstream}]
-      #;[(co-comment? x) (co-comment-text x)]
-      [(co-trailer? x) @string-append{
-        trailer
-        @(loop (co-trailer-dict x))
-        }]
-      [(symbol? x) @string-append{/@(symbol->string x)}]
-      [(number? x) @number->string{@x}]
-      [(string? x) (bytes->string/utf-8 (string->bytes/latin-1 x))]
-      [else (format "~a" x)])))
\ No newline at end of file
+(define (cosexpr->bytes x)
+  (bytes-append
+   (string->bytes/latin-1
+    (let loop ([x x])
+      (cond
+        [(co-version? x)
+         @string-append{%%PDF-@(number->string (co-version-num x))}]
+        [(co-header? x) (loop (co-header-string x))]
+        [(co-array? x)
+         @string-append{[ @(string-join (map loop (co-array-items x)) " ") ]}]
+        [(co-io? x)
+         @string-append{
+          @(loop (co-io-idx x)) @(loop (co-io-rev x)) obj
+          @(loop (co-io-thing x))
+          endobj
+
+          }]
+        [(co-dict? x)
+         @string-append{
+          <<
+          @(string-join
+            (for/list ([(k v) (in-hash (co-dict-dict x))])
+              @string-append{@(loop k) @(loop v)}) "\n")
+          >>}]
+        [(co-io-ref? x)
+         @string-append{@(loop (co-io-ref-idx x)) @(loop (co-io-ref-rev x)) R}]
+        [(co-stream? x)
+         @string-append{
+          @(loop (co-stream-dict x))
+          stream
+          @(loop (co-stream-data x))
+          endstream
+          }]
+        #;[(co-comment? x) (co-comment-text x)]
+        [(co-trailer? x) @string-append{
+          trailer
+          @(loop (co-trailer-dict x))
+          }]
+        [(symbol? x) @string-append{/@(symbol->string x)}]
+        [(number? x) @number->string{@x}]
+        [(string? x) x]
+        [else (format "~a" x)]))) #"\n"))
\ No newline at end of file