The GetBacklinkData command will return the citation and trust flow scores of the source and destination URLs.
If you require the trust and citation flow scores of the various referring domains this can be retrieved using the 'ShowDomainInfo' option which will add this data to the 'DomainsInfo' datatable in the reply
But if you require the citation flow of the destination domain itself as well you will need to make a separate call to GetIndexItemInfo for the domain.