title: aov formula error term: contradictory examples
body: <p>I've seen two basic approaches to generic formulas for within-subjects designs in R/<code>aov()</code> (<code>R</code> = random, <code>X</code> = dependent, <code>W</code>? = within, <code>B</code>? = between):</p>
  
  <pre><code># Pure within: 
      X ~ Error(R/W1*W2...)
  # or  
      X ~ (W1*W2...) + Error(R/(W1*W2...))
  
  # Mixed:
      X ~ B1*B2*... + Error(R/W1*W2...)
  # or  
      X ~ (B1*B2*...W1*W2...) + Error(R/(W1*W2...)+(B1*B2...))
  </code></pre>
  
  <p>That is, some advise never putting <code>W</code> factors outside the error term or <code>B</code> factors inside, while others put all (<code>B</code>, <code>W</code>) factors outside and inside, indicating in the error term which are nested within R.</p>
  
  <p>Are these simply notational variants? Is there any reason to prefer one to the other as a default for performing ANOVA using <code>aov()</code>? </p>