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?
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.
i don't know