In our example above, we're looking for papers about photosynthesis, and we want them from two very specific sources.
Google Scholar Search By Author
Many research projects benefit tremendously by containing citations and information from authors who are experts in their fields. Google Scholar makes it easy to find authors, simply by using the author: operator in front of the writer's name.
This parameter not only tells Google Scholar that you're looking for someone, but that you are looking for that word (green) as attached to an author rather than just on the page somewhere.
How to Frame Your Search
The word "photosynthesis" is right after the author tag, then the other author's name in quotes. Using quotes in searches tells Google that you're interested in those words, exactly in that sequence, and in that exact proximity.
author:green photosynthesis "tp buttz"