@article {weber2009laudation,
	title = {Laudatio Jens H{\o}yrup},
	journal = {Sartoniana},
	volume = {22},
	year = {2009},
	pages = {5{\textendash}7},
	author = {Weber, Erik and Heeffer, Albrecht}
}
@incollection {370857,
	title = {Learning concepts through the history of mathematics: the case of symbolic algebra.},
	booktitle = {Philosophical dimensions in mathematics education},
	year = {2007},
	pages = {83{\textendash}103},
	publisher = {Springer},
	isbn = {978-0-387-71571-1},
	author = {Heeffer, Albrecht},
	editor = {Fran{\c c}ois, Karen and Van Bendegem, Jean Paul}
}
@article {heeffer2006logic,
	title = {The logic of disguise: {D}escartes{\textquoteright} discovery of the Sine Law},
	journal = {Historia scientiarum. International Journal of the History of Science Society of Japan},
	volume = {16},
	number = {2},
	year = {2006},
	pages = {144{\textendash}165},
	abstract = {<p>The discovery of the sine law of refraction by Decartes has been a source of controversy since its first publication in 1637. Scholars describe Descartes demonstration of the law as inadequate and implausible or see in his proof an attempt to cover up plagiarism. Most of this critique stems from a lack of understanding the Cartesian theory of explanation. Descartes aims in the Discourse to find undoubtable knowledge that serves as a basis for his natural philosophy. In his Principles of Philosophy he deduces from his metaphysics several laws of nature and additional rules. However, for the explanation on physical phenomena, Descartes adopts a method different from the one proposed in his Discourse. This paper discusses the logical structure of the demonstration and provides an analysis of the premises and conclusions used in the derivation of the sine law. It is argued that Descartess explanation of refraction is a continuation of the perspectivists tradition and, ironically, Fermats account of 1662 is better application of the Cartesian method.</p>},
	author = {Heeffer, Albrecht}
}
