@MISC{LEIBNIZ1.MIZ,
  AUTHOR = {P\k{a}k, Karol},
  TITLE = {Leibniz's Series for Pi},
  NOTE = {This work has been financed by the
    resources of the Polish National Science Centre granted by decision
    no. DEC-2012/07/N/ST6/02147.},
  SECTION1 = {Preliminaries},
  SECTION2 = {Euler Transformation},
  SECTION3 = {Main Theorem},
  DAY = {18},
  MONTH = {October},
  YEAR = {2016},
  ADDRESS1 = {Institute of Informatics\\University of Bia{\l}ystok\\Konstantego Cio{\l}kowskiego 1M, 15-245 Bia{\l}ystok\\Poland},
  SUMMARY = {In this article we prove the Leibniz's Series for Pi
  which states that $$\frac{\pi}{4}=\sum_{n=0}^\infty \frac{(-1)^n}{2\cdot n+1}.$$
  \par The formalization follows K. Knopp \cite{Knopp}.
  {L}eibniz's {S}eries for {P}i is listed as \#26 at Freek Wiedijk's
   list of ``Top 100 mathematical theorems" \cite{Freek-100-theorems}.}}

@BOOK{Knopp,
  AUTHOR =       {Knopp, Konrad},
  TITLE =        {Infinite Sequences and Series},
  YEAR=1956,
  PUBLISHER = {Dover Publications},
  isbn =         {978-0-486-60153-3}}
