The Kitchin Research Group

(with-current-buffer
        (url-retrieve-synchronously
"http://xisbn.worldcat.org/webservices/xid/isbn/9780309095211?method=getMetadata&format=json&fl=*")
      (buffer-substring url-http-end-of-headers (point-max)))

(with-current-buffer
        (url-retrieve-synchronously
"http://xisbn.worldcat.org/webservices/xid/isbn/9780309095211?method=getMetadata&format=json&fl=*")
      (json-read-from-string
        (buffer-substring url-http-end-of-headers (point-max))))

((list .
       [((oclcnum .
                  ["224969280" "70060944" "756709329" "804792476" "817950524" "833420290" "836338922" "704551455"])
         (title . "To recruit and advance women students and faculty in science and engineering")
         (isbn .
               ["9780309095211"])
         (year . "2006")
         (ed . "[Online-Ausg.]")
         (author . "Committee on the Guide to Recruiting and Advancing Women Scientists and Engineers in Academia, Committee on Women in Science and Engineering, Policy and Global Affairs, National Research Council of the National Academies.")
         (city . "Washington, D.C.")
         (lang . "eng")
         (lccn .
               ["2006016786"])
         (form .
               ["BC"])
         (publisher . "National Academies Press")
         (url .
              ["http://www.worldcat.org/oclc/224969280?referer=xid"]))])
 (stat . "ok"))

(let* ((results  (with-current-buffer
                    (url-retrieve-synchronously
                     "http://xisbn.worldcat.org/webservices/xid/isbn/9780309095211?method=getMetadata&format=json&fl=*")
                  (json-read-from-string
                   (buffer-substring url-http-end-of-headers (point-max)))))
       (status (cdr (nth 1 results)))
       (metadata (aref (cdar results) 0)))

  (unless (string= "ok" status)
    (error "Status is %s" status))

  (concat "@book{,\n"
          (mapconcat (lambda (x)
                       (format "  %s={%s}," (car x) (cdr x)))
                     metadata "\n")
          "}\n"))

(defun isbn-to-bibtex (isbn bibfile)
  "Get bibtex entry for ISBN and insert it into BIBFILE unless an
entry with the generated key already exists in the file."
  (interactive
   (list
    (read-input
     "ISBN: "
     ;; now set initial input
     (cond
      ;; If region is active and it starts with a number, we use it
      ((and  (region-active-p)
             (s-match "^[0-9]" (buffer-substring (region-beginning) (region-end))))
       (buffer-substring (region-beginning) (region-end)))
      ;; if first entry in kill ring starts with a number assume it is an isbn
      ;; and use it as the guess
      ((if (s-match "^[0-9]" (car kill-ring))
           (car kill-ring)))
      ;; type or paste it in
      (t
       nil)))
    (ido-completing-read
     "Bibfile: "
     (append (f-entries "." (lambda (f) (f-ext? f "bib")))
             org-ref-default-bibliography))))

  (let* ((results (with-current-buffer
                      (url-retrieve-synchronously
                       (format
                        "http://xisbn.worldcat.org/webservices/xid/isbn/%s?method=getMetadata&format=json&fl=*"
                        isbn))
                    (json-read-from-string
                     (buffer-substring url-http-end-of-headers (point-max)))))
         (status (cdr (nth 1 results)))
         (metadata (aref (cdar results) 0))
         (new-entry)
         (new-key))

    ;; check if we got something
    (unless (string= "ok" status)
      (error "Status is %s" status))

    ;; construct an alphabetically sorted bibtex entry. I assume ISBN numbers go
    ;; with book entries.
    (setq new-entry
          (concat "\n@book{,\n"
                  (mapconcat
                   'identity
                   (loop for field in (-sort 'string-lessp (mapcar 'car metadata))
                         collect
                         (format "  %s={%s}," field (cdr (assoc field metadata))))
                   "\n")
                  "\n}\n"))

    ;; build entry in temp buffer to get the key so we can check for duplicates
    (setq new-entry (with-temp-buffer
                      (insert new-entry)
                      (org-ref-clean-bibtex-entry)
                      (setq new-key (bibtex-key-in-head))
                      (buffer-string)))
    (find-file bibfile)
    (goto-char (point-min))
    (when (search-forward new-key nil t)
      (beep)
      (setq new-key (read-input
                     (format  "%s already exists. Enter new key (C-g to cancel): " new-key)
                     new-key)))
    (goto-char (point-max))
    (insert new-entry)
    ;; set key. It is simplest to just replace it, even if it is the same.
    (bibtex-beginning-of-entry)
    (re-search-forward bibtex-entry-maybe-empty-head)
    (if (match-beginning bibtex-key-in-head)
        (delete-region (match-beginning bibtex-key-in-head)
                       (match-end bibtex-key-in-head)))
    (insert new-key)
    (bibtex-fill-entry)
    (save-buffer)))