xslt - XSLT: XML 属性を XHTML クラスに変換しますか?

Question

次のような内容の TEI XML ドキュメントがあります。

<said who="#Bernard">“I see a ring,” said Bernard, “hanging above
me.  It quivers and hangs in a loop of light.”&lt;/said>

<said who="#Susan">“I see a slab of pale yellow,” said Susan,
spreading away until it meets a purple stripe.”&lt;/said>

そして、次のように XHTML を出力したい:

<p class="Bernard">“I see a ring,” said Bernard, “hanging above
me.  It quivers and hangs in a loop of light.”&lt;/p>

<p class="Susan">“I see a slab of pale yellow,” said Susan,
spreading away until it meets a purple stripe.”&lt;/p>

属性の値を XHTML クラスにマップする最良の方法は何ですか?