@article{doi:10.1302/0301-620X.72B2.2312555,
author = {Simmons, ED and Graham, HK and Szalai, JP},
title = {Interobserver variability in grading Perthes' disease},
journal = {The Journal of Bone & Joint Surgery British Volume},
volume = {72-B},
number = {2},
pages = {202-204},
year = {1990},
doi = {10.1302/0301-620X.72B2.2312555},
url = {https://doi.org/10.1302/0301-620X.72B2.2312555}
}