@article{carretal,
  author = {Daniel B. Carr and Anthony R. Olsen and Denis White},
  title = {Hexagon Mosaic Maps for Display of Univariate and Bivariate Geographical Data},
  journal = {Cartography and Geographic Information Systems},
  volume = {19},
  number = {4},
  pages = {228-236},
  year  = {1992},
  publisher = {Taylor & Francis},
  doi = {10.1559/152304092783721231}
}
