  An exact Lagrangian submanifold $L$ in the symplectization of standard
contact $(2n-1)$-space with Legendrian boundary $\Sigma$ can be glued to itself
along $\Sigma$. This gives a Legendrian embedding $\Lambda(L,L)$ of the double
of $L$ into contact $(2n+1)$-space. We show that the Legendrian isotopy class
of $\Lambda(L,L)$ is determined by formal data: the manifold $L$ together with
a trivialization of its complexified tangent bundle. In particular, if $L$ is a
disk then $\Lambda(L,L)$ is the Legendrian unknot.
