Mesozoic Birds: Above the Heads of Dinosaurs - Google Books

https://books.google.de/books?id=2MQeh1KCp7sC&pg=PA311#v=onepage

Our knowledge of the origin and early evolution of birds has exploded in the past ten to fifteen years. In the 1990s alone, scientists became aware of approximately three times more species of early birds than were previously known, marking the first 85…