How to trigger specific workflow and not all?

Suppose that I use these workflow config (an actual one, for building and deploying 2 distinct branches of a program, for EL 6 and 7 RPM repositories):

workflows:
  version: 2
  build-deploy-stable:
    jobs:
      - el6-stable
      - el7-stable
      - deploy-stable:
          context: org-global
          requires:
            - el6-stable
            - el7-stable
          filters:
            branches:
              only: master
  build-deploy-mainline:
    jobs:
      - el6-mainline
      - el7-mainline
      - deploy-mainline:
          context: org-global
          requires:
            - el6-mainline
            - el7-mainline
          filters:
            branches:
              only: master      

So I have really 2 workflows named “build-deploy-stable” and “build-deploy-mainline”.

I know I can trigger all workflows to be run using API.

But how can I fire only specific workflow to be run via API? I could not find a way.