Quiero usarcontraer opciones de datos principales. Necesito un comportamiento de acordeón tradicional: todos los elementos plegables debajo del elemento primario especificado deben cerrarse cuando se muestra un elemento plegable. Pero no funciona. No sé si es por mi colapso anidado o si hago algo mal.

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<div class="content-nav">
  <a data-parent="#content-articles" role="button" data-toggle="collapse" aria-expanded="false" aria-controls="content-nav__book_third" href="#content-nav__book_third" class="content-nav__book content-nav__book_third">3</a>
  <a data-parent="#content-articles" role="button" data-toggle="collapse" aria-expanded="false" aria-controls="content-nav__book_second" href="#content-nav__book_second" class="content-nav__book content-nav__book_second">2</a>
  <a data-parent="#content-articles" role="button" data-toggle="collapse" aria-expanded="true" aria-controls="content-nav__book_first" href="#content-nav__book_first" class="content-nav__book content-nav__book_first">1</a>
</div>
<!--.content-nav-->
<div id="content-articles">
  <div id="content-nav__book_third" class="content-article collapse">
    <div id="content-article__info_third-1" class="content-article__info collapse">
      Book 3 article 1
    </div>
    <!--.content-article__info-->
    <div id="content-article__info_third-2" class="content-article__info collapse">
      Book 3 article 2
    </div>
    <!--.content-article__info-->
    <div id="content-article__info_third-3" class="content-article__info collapse">
      Book 3 article 3
    </div>
    <!--.content-article__info-->

    <div class="content-article__plan">
      <a data-parent="#content-nav__book_third" data-toggle="collapse" aria-expanded="false" aria-controls="content-article__info_third-1" href="#content-article__info_third-1" class="content-article__plan-link content-article__plan-link_third-1">Link - Book 3 article 1</a>
      <a data-parent="#content-nav__book_third" data-toggle="collapse" aria-expanded="false" aria-controls="content-article__info_third-2" href="#content-article__info_third-2" class="content-article__plan-link content-article__plan-link_third-2">Link - Book 3 article 2</a>
      <a data-parent="#content-nav__book_third" data-toggle="collapse" aria-expanded="false" aria-controls="content-article__info_third-3" href="#content-article__info_third-3" class="content-article__plan-link content-article__plan-link_third-3">Link - Book 3 article 3</a>
    </div>
    <!--.content-article__plan-->
  </div>
  <!--.content-article-->

  <div id="content-nav__book_second" class="content-article collapse">
    <div id="content-article__info_second-1" class="content-article__info collapse">
      Book 2 article 1
    </div>
    <!--.content-article__info-->
    <div id="content-article__info_second-2" class="content-article__info collapse">
      Book 2 article 2
    </div>
    <!--.content-article__info-->
    <div id="content-article__info_second-3" class="content-article__info collapse">
      Book 2 article 3
    </div>
    <!--.content-article__info-->

    <div class="content-article__plan">
      <a data-parent="#content-nav__book_second" data-toggle="collapse" aria-expanded="false" aria-controls="content-article__info_second-1" href="#content-article__info_second-1" class="content-article__plan-link content-article__plan-link_second-1">Link - Book 2 article 1</a>
      <a data-parent="#content-nav__book_second" data-toggle="collapse" aria-expanded="false" aria-controls="content-article__info_second-2" href="#content-article__info_second-2" class="content-article__plan-link content-article__plan-link_second-2">Link - Book 2 article 2</a>
      <a data-parent="#content-nav__book_second" data-toggle="collapse" aria-expanded="false" aria-controls="content-article__info_second-3" href="#content-article__info_second-3" class="content-article__plan-link content-article__plan-link_second-3">Link - Book 2 article 3</a>
    </div>
    <!--.content-article__plan-->
  </div>
  <!--.content-article-->

  <div id="content-nav__book_first" class="content-article collapse show">
    <div id="content-article__info_first-1" class="content-article__info collapse">
      Book 1 article 1
    </div>
    <!--.content-article__info-->
    <div id="content-article__info_first-2" class="content-article__info collapse">
      Book 1 article 2
    </div>
    <!--.content-article__info-->
    <div id="content-article__info_first-3" class="content-article__info collapse">
      Book 1 article 3
    </div>
    <!--.content-article__info-->

    <div class="content-article__plan">
      <a data-parent="#content-nav__book_first" data-toggle="collapse" aria-expanded="false" aria-controls="content-article__info_first-1" href="#content-article__info_first-1" class="content-article__plan-link content-article__plan-link_first-1">Link - Book 1 article 1</a>
      <a data-parent="#content-nav__book_first" data-toggle="collapse" aria-expanded="false" aria-controls="content-article__info_first-2" href="#content-article__info_first-2" class="content-article__plan-link content-article__plan-link_first-2">Link - Book 1 article 2</a>
      <a data-parent="#content-nav__book_first" data-toggle="collapse" aria-expanded="false" aria-controls="content-article__info_first-3" href="#content-article__info_first-3" class="content-article__plan-link content-article__plan-link_first-3">Link - Book 1 article 3</a>
    </div>
    <!--.content-article__plan-->
  </div>
  <!--.content-article-->
</div>
<!--#content-articles-->

Probablemente tuve que agregar algunos js. Pero el código no debe ser redundante.