@book{elaydi2005,
  author    = {Elaydi, Saber},
  title     = {An Introduction to Difference Equations},
  publisher = {Springer},
  year      = {2005},
  edition   = {3}
}

@book{rudin1976,
  author    = {Rudin, Walter},
  title     = {Principles of Mathematical Analysis},
  publisher = {McGraw-Hill},
  year      = {1976},
  edition   = {3}
}
