@article{ref1,
title="A speed and frequency substandard for tachograph calibration equipment",
journal="Forensic science international",
year="1984",
author="Russell, J. R. and Lambourn, R. F.",
volume="24",
number="1",
pages="81-86",
abstract="The process of calibrating a tachograph makes use of a mechanical head drive unit and an electronic clock tester. Both these devices should be checked against a standard at 6-month intervals. The design of such a substandard, based on a highly stable 1 MHz crystal oscillator, is described.<p /> <p>Language: en</p>",
language="en",
issn="0379-0738",
doi="",
url="http://dx.doi.org/"
}