Dutch records. Baertji md. to Willem Pieterse Van Slyke of Amersfoort, Utrecht, Netherland

Good day. I am interested in finding out the true name of Willem Pieterse Van Slyke's wife. I have seen it as Baertji only, b. 1636 & d. 1699. Willem is the nephew of Cornelis Antonissen Van Slyke & Ots-Toch. I am hoping that someone has documentation for "Baertji."  I appreciate your help. Thank you.