@techreport{jl_2009/ideal_operator_el_tr,
	title = "Ideal Downward Refinement in the EL Description Logic",
	author = "Jens Lehmann and Christoph Haase",
	institution = "Universit{\"a}t of Leipzig",
	year = "2009",
}

Please send me an email if the BibTeX export is incorrect/incomplete.