1. Assem, I., Simson, D., Skowronski, A.: Elements of the Representation Theory of Associative Algebras, vol 1, Techniques of Representation Theory. Cambridge University Press (2006)
2. Cohen, R. L., Godin, V.: A polarized view of string topology, Topology, geometry, and quantum field theory , Cambridge: Cambridge University Press. London Math. Soc. Lect. Notes 308, 127–154 (2004)
3. Gabriel, P.: Unzerlegbare Darstellungen I. Manuscripta Math. 6, 71–103 (1972)
4. Gabriel, P.: Indecomposable representations II. Symposia Mat. Inst. Naz. Alta Mat. 11, 81–104 (1973)
5. González, A., Lupercio, E., Segovia, C., Uribe, B.: Orbifold Topological Quantum Field Theories in Dimension 2,365