@article{hamilton:2001:fgf,
    author = {A. J. S. Hamilton},
     title = {Formulae for growth factors in expanding universes
              containing matter and a cosmological constant},
   journal = {Monthly Notices Roy. Astronom. Soc.},
      year = {2001},
    volume = {322},
    number = {2},
     pages = {419–425},
       doi = {10.1046/j.1365-8711.2001.04137.x}}