title: Adding greek character to axis title
body: <p>I want to add a greek character to the y-axis of my barplot in R.<br>
  The problem is that I need this character to be integrated in the title. I want to write: </p>
  
  <pre><code>Diameter of aperture ("mu"m)
  </code></pre>
  
  <p>in the axis label.</p>
  
  <p>With</p>
  
  <pre><code>ylab=expression()
  </code></pre>
  
  <p>I can write the greek character, with</p>
  
  <pre><code>ylab="axis title"
  </code></pre>
  
  <p>I can write the title with proper spaces between the words.</p>
  
  <p>But I can't find a way to put all these together and write a proper label with a greek word in the axis label. I hope I was clear enough.</p>