Where is the Open Graph? (SOLVED)

Hello,

I activated Open Graph in the admin menu of Yoast SEO, but where can I see it in the source-code? I can´t find anything there. I deactivated the Open Graph in a plugin for social share (because I already activated it in SEO), so I would like to know where I can find it? It is nowhere in the head-area.

Regards

http://wordpress.org/extend/plugins/wordpress-seo/