@article{Kelley_1964,<br/><span class="tab"></span> title={De Origine Feudorum: The Beginnings of an Historical Problem},<br/><span class="tab"></span> volume={39},<br/><span class="tab"></span> ISSN={2040-8072},<br/><span class="tab"></span> url={http://dx.doi.org/10.2307/2852726},<br/><span class="tab"></span> DOI={10.2307/2852726},<br/><span class="tab"></span> number={2},<br/><span class="tab"></span> journal={Speculum},<br/><span class="tab"></span> publisher={University of Chicago Press},<br/><span class="tab"></span> author={Kelley,<br/><span class="tab"></span> Donald R.},<br/><span class="tab"></span> year={1964},<br/><span class="tab"></span> month=apr,<br/><span class="tab"></span> pages={207–228} }