(defun my-show-article-other-window ()
  (interactive)
  "Show article in a seperate window from Gnus summary buffer"
  (mapcar
   (lambda (article)
     (elscreen-find-and-goto-by-buffer gnus-summary-buffer)
     (let ((show-article
            (lambda ()
              (gnus-summary-select-article nil ‘force ‘pseudo article)
              (gnus-summary-select-article-buffer)
              (let ((new-name (concat "*Article " gnus-newsgroup-name
                                      "/" (number-to-string article) "*")))
                (if (get-buffer new-name) (kill-buffer (get-buffer new-name)))
                (rename-buffer new-name)
                new-name))))
       (elscreen-create)
       (switch-to-buffer
        (save-window-excursion
          (save-excursion
            (if (gnus-buffer-live-p gnus-article-buffer)
                (let ((old-article (cdr gnus-article-current))
                      (new-name (funcall show-article)))
                  (gnus-summary-select-article nil ‘force ‘pseudo old-article)
                  new-name)
              (funcall show-article))))))
     (gnus-summary-work-articles nil))))

(define-key gnus-summary-mode-map [(control return)] ‘my-show-article-other-window)