@article{10_1090_S0894_0347_1991_1102580_2,
     author = {Eliashberg, Yakov},
     title = {New invariants of open symplectic and contact manifolds},
     journal = {Journal of the American Mathematical Society},
     pages = {513--520},
     publisher = {mathdoc},
     volume = {04},
     number = {3},
     year = {1991},
     doi = {10.1090/S0894-0347-1991-1102580-2},
     url = {http://geodesic.mathdoc.fr/articles/10.1090/S0894-0347-1991-1102580-2/}
}