Question: What is the birthdate of this Dutch professional football manager and former player, who was a new signing for the 1998-99 FC Barcelona season?
Sentence (from "1998–99 FC Barcelona season"): Barcelona enjoyed a great season with their new signings Ronald de Boer, Patrick Kluivert, Frank de Boer, Mauricio Pellegrino, Boudewijn Zenden and Phillip Cocu.
Relevant evidence: Yes