1. G. Gilli and P.Gilli , The Nature of the Hydrogen Bond , Oxford University Press , Oxford, UK , 2009
2. G. R. Desiraju and T.Steiner , The Weak Hydrogen Bond in Structural Chemistry and Biology , Oxford University Press , New York , 1999
3. S. Scheiner , Hydrogen Bonding. A Theoretical Perspective , Oxford University Press , New York , 1997
4. Halogen bonding: the σ-hole
5. Expansion of the σ-hole concept