<style type="text/css">
.mine {color: red}
.his {color: green}
.ourcode {font-family: Courier}
.ourref {font-style:italic}
</style>

...
<p class="mine ourcode">x=y</p>
<p class="his ourref"> [16]</p>
<p class="mine ourref"> [18]</p>
<p class="his ourcode">y=3</p>