  Pion-meson-exchange nucleon-nucleon potentials are derived for two nucleons
in the intermediate states. The mesons we include are (i) pseudoscalar mesons:
$\pi, \eta, \eta'$; (ii) vector mesons: $\rho, \omega, \phi$; (iii) scalar
mesons: $a_{0}(980), \varepsilon(760), f_{0}(975)$; and (iv) the $J=0$
contribution from the Pomeron. Strong dynamical pair suppression is assumed,
and at the nucleon-nucleon-meson vertices Gaussian form factors are
incorporated into the relativistic two-body framework using a dispersion
representation for the pion- and meson-exchange amplitudes. The Fourier
transformations are performed using factorization techniques for the energy
denominators. The potentials are first calculated in the adiabatic
approximation to all planar and crossed three-dimensional momentum-space
$\pi$-meson diagrams. Next, we calculate the $1/M$ corrections.
