Maximal nonsymmetric entropy leads naturally to Zipf's law
  As the most fundamental empirical law, Zipf's law has been studied from many aspects. But its meaning is still an open problem. Some models have been constructed to explain Zipf's law. In the letter, a new concept named nonsymmetric entropy was introduced, maximizing nonsymmetric entropy leads naturally to Zipf's law. 
Chengshi Liu