@article {arici2016pimsner,
	title = {Pimsner algebras and Gysin sequences from principal circle actions},
	journal = {Journal of Noncommutative Geometry},
	volume = {10},
	year = {2016},
	pages = {29{\textendash}64},
	issn = {1661-6952},
	doi = {10.4171/jncg/228},
	url = {http://hdl.handle.net/2066/162951},
	author = {Francesca Arici and Jens Kaad and Giovanni Landi}
}
