  We present tight-binding models of 3D topological superconductors in class
DIII that support a variety of winding numbers. We show that gapless Majorana
surface states emerge at their boundary in agreement with the bulk-boundary
correspondence. At the presence of a Zeeman field the surface states become
gapped and the boundary behaves as a 2D superconductor in class D. Importantly,
the 2D and 3D winding numbers are in agreement signifying that the topological
order of the boundary is induced by the order of the 3D bulk. Hence, the
boundary of a 3D topological superconductor in class DIII can be used for the
robust realisation of localised Majorana zero modes.
