Collada animation node, how to write rotation as quaternion - collada

Question

I need to rewrite Euler rotations in a collada file as quaternions. I can`t find out how the quaternion representation would look like. Can anyone point me in the direction on how such a animation node would look like? (I just need to know how to write the Collada, the calculation is not the problem)
Sample with Euler Representation:
<animation>
<source id="ID72">
<float_array id="ID73" count="2">0 0.4</float_array>
<technique_common>
<accessor count="2" source="#ID73">
<param name="TIME" type="float"/>
</accessor>
</technique_common>
</source>
<source id="ID74">
<Name_array id="ID75" count="2">LINEAR LINEAR</Name_array>
<technique_common>
<accessor count="2" source="#ID75">
<param name="INTERPOLATION" type="Name"/>
</accessor>
</technique_common>
</source>
<source id="ID80">
<float_array id="ID81" count="2">0 -60</float_array>
<technique_common>
<accessor count="2" source="#ID81">
<param name="ANGLE" type="float"/>
</accessor>
</technique_common>
</source>
<sampler id="ID82">
<input semantic="INPUT" source="#ID72"/>
<input semantic="INTERPOLATION" source="#ID74"/>
<input semantic="OUTPUT" source="#ID80"/>
</sampler>
<channel source="#ID82" target="ID38/rotateY.ANGLE"/>
</animation>
<animation>
<source id="ID83">
<float_array id="ID84" count="2">0 0.4</float_array>
<technique_common>
<accessor count="2" source="#ID84">
<param name="TIME" type="float"/>
</accessor>
</technique_common>
</source>
<source id="ID85">
<Name_array id="ID86" count="2">LINEAR LINEAR</Name_array>
<technique_common>
<accessor count="2" source="#ID86">
<param name="INTERPOLATION" type="Name"/>
</accessor>
</technique_common>
</source>
<source id="ID91">
<float_array id="ID92" count="2">0 -40</float_array>
<technique_common>
<accessor count="2" source="#ID92">
<param name="ANGLE" type="float"/>
</accessor>
</technique_common>
</source>
<sampler id="ID93">
<input semantic="INPUT" source="#ID83"/>
<input semantic="INTERPOLATION" source="#ID85"/>
<input semantic="OUTPUT" source="#ID91"/>
</sampler>
<channel source="#ID93" target="ID38/rotateX.ANGLE"/>
</animation>
<animation>
<source id="ID94">
<float_array id="ID95" count="2">0 0.4</float_array>
<technique_common>
<accessor count="2" source="#ID95">
<param name="TIME" type="float"/>
</accessor>
</technique_common>
</source>
<source id="ID96">
<Name_array id="ID97" count="2">LINEAR LINEAR</Name_array>
<technique_common>
<accessor count="2" source="#ID97">
<param name="INTERPOLATION" type="Name"/>
</accessor>
</technique_common>
</source>
<source id="ID102">
<float_array id="ID103" count="2">-0 -0</float_array>
<technique_common>
<accessor count="2" source="#ID103">
<param name="ANGLE" type="float"/>
</accessor>
</technique_common>
</source>
<sampler id="ID104">
<input semantic="INPUT" source="#ID94"/>
<input semantic="INTERPOLATION" source="#ID96"/>
<input semantic="OUTPUT" source="#ID102"/>
</sampler>
<channel source="#ID104" target="ID38/rotateZ.ANGLE"/>
</animation>