Cornelius ‘Kees’ Hazevoet is a Dutch multiinstrumentist (piano, trumpet, clarinet) who has done thorough and extensive research on Don Byas. His discography and chronology in two parts is a groundbreaking source and reference for all-things Byas. He is listed as the main contributor in the acknowledgments section of the Chapman bio (btw, I am also listed 😜). I have exchanged a lot of information with Kees over the years. He is one the nicest and most generous researchers I have come across in my never-ending Tete Montoliu project. And he is a member of these forums, under the name of Caravan.
And yes, Chapman has screwed up the right chronological order in some places. And he has also included some factual mistakes on the years spent by Don Byas in Spain and Portugal.