@article{article52161237,
title   = {Histobacteriological assessment of nonvital teeth after ultrasonic root canal instrumentation},
author = {Rodrigues, H H and Biffi, J C G},
year = {1989},
doi = {10.1111/j.1600-9657.1989.tb00357.x},
journal   = {Endodontics and Dental Traumatology}
}