@article{Schafer2002,
author = {Schafer, J.L. and Graham, J.W.},
title= {Missing data: Our view of the state of the art},
year = {2002},
doi = {10.1037/1082-989X.7.2.147},
journal = {Psychological Methods},
volume = {7},
number = {2},
pages = {147‒177},
}