Finding your expert isn't a search problem. It is a graph problem.
Who has published in this field? Who sits at the intersection of immmigration law, human rights, and intellectual property — in this specific country? Who do the other experts cite when they need an authority?
Boolean search is fine for a couple of topics, if done accurately. Integrity is built for intersections, iteration and serendipity.
Every author, every institution, every co-authorship — mapped by topic hierarchy, queryable and auditable. You arrived with a query. You leave with a shortlist, a record for each name, and the receipts to back it up.