style399.csl

<?xml version="1.0" encoding="utf-8"?>
<style xmlns="http://purl.org/net/xbiblio/csl" class="in-text" version="1.0" demote-non-dropping-particle="never" default-locale="en-US">
  <citation>
    <sort>
      <key variable="citation-number"/>
    </sort>
    <layout prefix="[" suffix="]" delimiter=",">
      <text variable="citation-number"/>
    </layout>
  </citation>
</style>