title: Can't display x and y labels, when plotting with the quantreg command
body: <p>I'm trying to plot the result of the quantreg command, but the labels of the graph don't show up. I'm running this code:</p>
  
  <pre><code>plot(summary(qrg), parm="agua_esgoto", xlab = "Quantiles", ylab = "Piped water and sewage", main = "Figure 1")
  </code></pre>
  
  <p>This is the image that was returned:</p>
  
  <p><a href="https://i.stack.imgur.com/3b1uK.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/3b1uK.png" alt="enter image description here"></a></p>