how to add special glyphs

[Rob Sargent]

    I have added a "boxed
      x" and "CHECK MARK" to my document, but they do not get exported
      to pdf output.  They are in the .tex file, and do go through to
      the HTML.  So far I'm using these packages
      
    
> #+LaTeX_HEADER:
>         \usepackage[T1]{fontenc}
>       #+LaTeX_HEADER:
>         \usepackage{libertine}
>       #+LaTeX_HEADER:
>         \usepackage[margin=0.80in]{geometry}
>       #+LaTeX_HEADER:
>         \usepackage{setspace}
>       #+LaTeX_HEADER:
>         \usepackage{enumitem}
>       #+LaTeX_HEADER:
>         \usepackage{endnotes}
>     
    (Bonus points for UTF8
      code for the opposite of "CHECK MARK"?)