Erik R Loopstra, Gerrit M Bonnema, Harmen K Van Der Schoot, Gerjan P Veldhuis, Yim Bun P Kwan: Positioning device having two object holders. ASM Lithography, Pillsbury Winthrop, July 17, 2001: US06262796 (335 worldwide citation)

A positioning device has first and second object holders that are guided over a guiding surface extending parallel to an X-direction and parallel to a Y-direction perpendicular to the X-direction and which are displaceable over the guiding surface from a first position into a second position by mean ...