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's league start was slower in early season but Barcelona turnaround to secure La Liga in late-May, but Barcelona crashed out of the UEFA Champions League, following an another lackluster performance in the First Group Phase.
Relevant evidence: No