@article {duarte2004differences,
	title = {From Differences to Derivatives},
	year = {2004},
	note = {<p>n/a</p>
},
	publisher = {Institute of Mathematics and Informatics Bulgarian Academy of Sciences},
	abstract = {<p>n/a</p>
},
	author = {Duarte Ortigueira, M. and Coito, F.}
}
