1. K. T. Chen, Iterated Integrals and exponential homomorphisms, Proc. London Math. Soc. (3) 4 (1954), 502–512. MR 17, 394.
2. K. T. Chen, Integration of paths, geometric Invariants and a generalized Baker-Hausdorff formula, Ann. of Math. (2) 65 (1957), 163–178. MR 19, 12.
3. K. T. Chen, Integration of paths-a faithful representation of paths by поп-commutative formal power series, Trans. Amer. Math. Soc. 89 (1958), 395–407. MR 21 #4992.
4. K. T. Chen, Exponential isomorphism for vector spaces and its connection with Lie groups,J. London Math. Soc. 33 (1958), 170–177. MR 21 #4991.
5. K. T. Chen, Formal differential equations, Ann. of Math. (2) 73 (1961), 110–133. MR 27 #371.