diff --git a/bibtex-completion.el b/bibtex-completion.el
index 19076a5..0825b97 100644
--- a/bibtex-completion.el
+++ b/bibtex-completion.el
@@ -762,6 +762,24 @@ Returns nil if no PDF is found."
   (or (bibtex-completion-find-pdf-in-field key-or-entry)
       (bibtex-completion-find-pdf-in-library key-or-entry find-additional)))
 
+(defun bibtex-completion-find-note-file-default (entry-key)
+  "Find note file associated from BibTeX’s ENTRY-KEY in the default directory.
+The default directory is `bibtex-completion-notes-path'.  If the
+note file doesn’t exist, return nil."
+  (and bibtex-completion-notes-path
+       (f-directory? bibtex-completion-notes-path)
+       (f-file? (f-join bibtex-completion-notes-path
+                        (s-concat entry-key
+                                  bibtex-completion-notes-extension)))))
+
+(defcustom bibtex-completion-find-note-file-fns
+  (list #'bibtex-completion-find-note-file-default)
+  "List of functions to use to find note files.
+The functions should accept one argument: the entry-key of the
+BibTeX entry."
+  :group 'bibtex-completion
+  :type 'list)
+
 (defun bibtex-completion-prepare-entry (entry &optional fields do-not-find-pdf)
   "Prepare ENTRY for display.
 ENTRY is an alist representing an entry as returned by
@@ -781,11 +799,10 @@ find a PDF file."
            ; Check for notes:
            (entry (if (or
                        ;; One note file per entry:
-                       (and bibtex-completion-notes-path
-                            (f-directory? bibtex-completion-notes-path)
-                            (f-file? (f-join bibtex-completion-notes-path
-                                             (s-concat entry-key
-                                                       bibtex-completion-notes-extension))))
+                       (cl-some #'identity
+                                (mapcar (lambda (fn)
+                                          (funcall fn entry-key))
+                                        bibtex-completion-find-note-file-fns))
                        ;; All notes in one file:
                        (and bibtex-completion-notes-path
                             (f-file? bibtex-completion-notes-path)
@@ -795,7 +812,7 @@ find a PDF file."
            ; Remove unwanted fields:
            (entry (if fields
                        (--filter (member-ignore-case (car it) fields) entry)
-                     entry)))
+                    entry)))
       ;; Normalize case of entry type:
       (setcdr (assoc "=type=" entry) (downcase (cdr (assoc "=type=" entry))))
       ;; Remove duplicated fields: