APA Style
      BARTNIK, R. et al (2016).
    Optimum Investment Strategy in the Power Industry
Mathematical Models .
    Atlantis Press and the author:
  Springer Cham.
  
MLA Style
      BARTNIK, Ryszard. et al.
    "Optimum Investment Strategy in the Power Industry
Mathematical Models".
    
    Atlantis Press and the author:
  Springer Cham,
  2016.
  Text.