The code
[[su_quote cite="Albert <a href="https://google.com/">Einstein</a>"]E=MC^2[/su_quote]]
The result
[su_quote cite=”Albert Einstein“]E=MC^2[/su_quote]
The code
[[su_quote cite='Albert <a href="https://google.com/">Einstein</a>']E=MC^2[/su_quote]]
The result
[su_quote cite=’Albert Einstein‘]E=MC^2[/su_quote]