@article{doi:10.1302/0301-620X.73B1.1991778,
author = {Ohzono, K and Saito, M and Takaoka, K and Ono, K and Saito, S and Nishina, T and Kadowaki, T},
title = {Natural history of nontraumatic avascular necrosis of the femoral head},
journal = {The Journal of Bone & Joint Surgery British Volume},
volume = {73-B},
number = {1},
pages = {68-72},
year = {1991},
doi = {10.1302/0301-620X.73B1.1991778},
url = {https://doi.org/10.1302/0301-620X.73B1.1991778}
}