Acknowledgements
Many of the basic ideas behind this paper were developed in collaboration with James Dolan. We would also like to thank Lawrence Breen, Misha Kapranov, John Power, James Stasheff and Ross Street for useful discussions and correspondence. J.B. is grateful to the Mathematical Institute of the University of Munich for their hospitality while some of this work was done. We thank Joe Moeller and especially Jason Erbele for typesetting this new version of the paper in 2019.
Original source: arXiv:q-alg/9511013v2