@ARTICLE{JarVai75,
  author = {J\"arvinen, O. and V\"ais\"anen, R. A.},
  title = {Estimating relative densities of breeding birds by the line transect
	method},
  journal = {Oikos},
  year = {1975},
  volume = {26},
  pages = {316--322},
  subdatabase = {distance}
}