Rendering of the source text

<?xml version="1.0"?>
<model xmlns="http://www.cellml.org/cellml/1.1#" xmlns:cmeta="http://www.cellml.org/metadata/1.0#" cmeta:id="TJoint" name="TJoint">

<import xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="Units.cellml">
<units name="UnitP" units_ref="UnitP"/>
<units name="UnitQ" units_ref="UnitQ"/>
<units name="UnitR" units_ref="UnitR"/>

</import>

<component name="TJoint">
<variable name="Pi" public_interface="out" units="UnitP"/>
<variable name="Po" public_interface="in" units="UnitP"/>
<variable name="Qi1" public_interface="in" units="UnitQ"/>
<variable name="Qi2" public_interface="in" units="UnitQ"/>
<variable name="Qo" public_interface="out" units="UnitQ"/>

<math xmlns="http://www.w3.org/1998/Math/MathML">
<apply><eq/><ci>Pi</ci><ci>Po</ci></apply>
<apply><eq/><ci>Qo</ci><apply><plus/><ci>Qi1</ci><ci>Qi2</ci></apply></apply>
</math>

</component>

</model>