1. Iterated path integrals;Chen, Kuo Tsai;Bull. Amer. Math. Soc.,1977
2. Connections, holonomy and path space homology;Chen, Kuo Tsai,1975
3. [CS] Moira Chas and Dennis Sullivan, String topology, Preprint, arXiv:math/9911159, 1999.
4. Differential forms on loop spaces and the cyclic bar complex;Getzler, Ezra;Topology,1991