Zvon SVG reference

<svg width="8cm" height="3cm" version="1.1">
     <desc>Local URI references within ancestor's 'defs' element.</desc>
     <defs>
          <linearGradient id="Gradient01">
               <stop offset="20%" stop-color="#39F"/>
               <stop offset="90%" stop-color="#F3F"/>
          </linearGradient>
     </defs>
     <rect x="1cm" y="1cm" width="6cm" height="1cm" fill="url(#Gradient01)"/>
     <rect x=".01cm" y=".01cm" width="7.98cm" height="2.98cm" fill="none" stroke="blue" stroke-width=".02cm"/>
</svg>

Original SVG source