Add a source reference to org blocks

Question

During research, I often cite a passage from some website, a local document or org file. For context and later use, I always add the source reference after the block:

* Public transport
** Bus

Buses are used a lot:

#+BEGIN_QUOTE
The urban bus system, the world's most common form of public transport, uses a network of scheduled routes to move people through the city, alongside cars, on the roads.
#+END_QUOTE
Source: https://en.wikipedia.org/wiki/City#Transportation

I would really like the referenced source to be an actual property of the block. I don't know if there is a way for that, or in which direction I should look for this. I've tried looking at header arguments and org-ref, but they do not seem really applicable to my specific requirement.

Is there a standardized or recommended way of annotating org blocks with source references?