@article{Baksalary:2007,
  author  = "J. Baksalary and O. Baksalary and P. Kik",
  title   = "Generalizations of a property of orthogonal projectors",
  journal = "Linear Algebra and its Applications",
  volume  = "Vol. 420",
  number  = "iss. 1",
  pages   = "1--8",
  year    = "2007",
}