Baratelli M, Cabitza P, Parrini L
Ital J Orthop Traumatol. 1984 Dec;10(4):549-54.
The authors tested the reliability of a new method of evaluating osteoporosis and osteopenia radiographically. This is based on the calcaneal index, which can be correlated directly with Singh's femoral neck index and is inversely proportional to the age of the subjects tested.