error message when the link has & sign

I wonder if some one can explain what could have been wrong if I included the & in the link such as 
<a xlink:href="http://bunker.ca.boeing.com/bpi/servlet/InfoManager?env=PPU_PD&requestBPROC&proc=DWH04">
<text x="250" y="10" style="font-style:none; font-family:Vernada; font-weight:normal; fill:blue">
PPU_PD: DWH04 3.8.5.2.3 Adjust Inventory
</text>
</a>
Thank you in advance
Dung