@article{alti:pisigma-new,
  author = 	 {Thorsten Altenkirch and Nils Anders Danielsson and Andres L\"oh and Nicolas Oury},
  title = 	 {{$\Pi$}{$\Sigma$}: Dependent Types Without the Sugar},
 journal={Functional and Logic Programming},
  pages={40--55},
  year={2010},
  publisher={Springer}
}