@article{Skirbekk2012,
author = {Skirbekk, V. and Loichinger, E. and Weber, D. },
title= {Variation in cognitive functioning as a refined approach to comparing aging across countries},
year = {2012},
doi = {10.1073/pnas.1112173109},
journal = {Proceedings of the National Academy of Sciences },
volume = {109},
number = {3},
pages = {770--774},
}