<p>I would like to propose the following article:</p>

<blockquote>
  <p>Sheehan NA, Didelez V, Burton PR, Tobin MD (2008) <a href="http://www.plosmedicine.org/article/info%3adoi/10.1371/journal.pmed.0050177" rel="nofollow">Mendelian
  Randomisation and Causal Inference in Observational Epidemiology</a>.
  PLoS Med 5(8): e177. doi:10.1371/journal.pmed.0050177</p>
</blockquote>

<p>This paper is of some interest in relation to some threads on this site, in particular those related to inferring causality from observational studies.</p>
