For console.blog() post http://consoledotblog.com/2014/04/less-quick-tip-importing-via-reference

home-view.less

.article-teaser {
  .primary-box;
}

.filter-sidebar {
  .primary-box;
}

html-verbose-class.html

<div class="article-teaser primary-box">...</div>
<div class="filter-sidebar primary-box">...</div>

main-with-reference.css

.article-teaser {
  padding: 20px;
  margin: 10px;
  border: 1px solid #CCC;
  border-radius: 10px;
  background: #FFF;
}
.filter-sidebar {
  padding: 20px;
  margin: 10px;
  border: 1px solid #CCC;
  border-radius: 10px;
  background: #FFF;
}

main-with-reference.less

@import (reference) "mixins";
@import "home-view";

main.css

.primary-box {
  padding: 20px;
  margin: 10px;
  border: 1px solid #CCC;
  border-radius: 10px;
  background: #FFF;
}
.article-teaser {
  padding: 20px;
  margin: 10px;
  border: 1px solid #CCC;
  border-radius: 10px;
  background: #FFF;
}
.filter-sidebar {
  padding: 20px;
  margin: 10px;
  border: 1px solid #CCC;
  border-radius: 10px;
  background: #FFF;
}

main.less

@import "mixins";
@import "home-view";

mixins.less

.primary-box {
  padding: 20px;
  margin: 10px;
  border: 1px solid #CCC;
  border-radius: 10px;
  background: #FFF;
}