. . . . . "We show that the local system of orientations on the moduli space of J-holomorphic maps from a bordered Riemann surface is isomorphic to the pull-back of a local system defined on the product of the Lagrangian and its free loop space. The latter is defined using only the first and second Stiefel-Whitney classes of the Lagrangian. In the presence of an anti-symplectic involution, whose fixed locus is a relatively spin Lagrangian, we define open Gromov-Witten type invariants in genus zero."@en . . . . . "Orientability of moduli spaces and open Gromov-Witten invariants"@en . . .