The Preview panel in the Library window displays how the currently selected reference will be formatted in the bibliography by the current style. This Preview panel shows only one reference at a time.
To preview how multiple references will appear in a bibliography:
Select the references in the Library window.
From the Edit menu, select Output Styles and select the style that you would like to use.
From the Edit menu, select Copy Formatted (Ctrl+K) .
Use the Windows Clipboard Viewer Edit > Show Clipboard command from the Finder to view the contents of the Clipboard or Paste the formatted references into a word processor document.