@article{lim2007closed,
  title = {Closed-form solutions for lowpass filtering of 3D digital geometry},
  author = {Lim, IS and Hughes, D and John, NW},
  journal = {Electronics Letters},
  volume = {43},
  number = {9},
  pages = {503--505},
  year = {2007},
  publisher = {IET Digital Library}
}