Right to left edges in dot (Graphviz)

I'm trying to display edges going from right to left (i.e. backwards) using dot:

C <- A -> B

The best I could do was:

digraph {
  a -> b;
  c -> a [dir="back"];
  {rank=same;c a b}
}

..which is fine, except I don't like using c -> a when the edge is directed the other way.

So I wanted to share this solution (which didn't seem to be mentioned on SO) and check if I'm missing something obvious.

See: http://www.graphviz.org/doc/info/attrs.html#k:dirType