@ARTICLE{NUMBER12.MIZ,
  AUTHOR = {Grabowski, Adam},
  TITLE = {Elementary Number Theory Problems. {P}art {XII}},
  SECTION1 = {Preliminaries},
  SECTION2 = {Problem 42},
  SECTION3 = {Problem 43},
  SECTION4 = {Problem 51},
  SECTION5 = {Problem 51a},
  SECTION6 = {Problem 57},
  SECTION7 = {Problem 59},
  SECTION8 = {Problem 72},
  SECTION9 = {Problem 135},
  SECTION10 = {Problem 136},
  SECTION11 = {Problem 153},
  SECTION12 = {Problem 154},
  SECTION13 = {Problem 155},
  DAY = {18},
  MONTH = {December},
  YEAR = {2023},
  ADDRESS1 = {Faculty of Computer Science\\University of Bia{\l}ystok\\ Konstantego Cio{\l}kowskiego 1M, 15-245 Bia{\l}ystok\\Poland},
  SUMMARY = {In this paper another twelve problems from \cite{Sierpinski:1970} are formalized,
  using the Mizar formalism \cite{Mizar-State-2015,BancerekJAR:2018,Kornilowicz:2015:FC}, namely: 42, 43, 51, 51a, 57, 59, 72, 135, 136, 153, 
  154, and 155.}}
