Media type: E-Article Title: Spherical 2-Categories and 4-Manifold Invariants Contributor: Mackaay, Marco Published: Elsevier BV, 1999 Published in: Advances in Mathematics, 143 (1999) 2, Seite 288-348 Language: English DOI: 10.1006/aima.1998.1798 ISSN: 0001-8708 Origination: Footnote: Access State: Open Access