Buick 2007 LaCrosse Owner's Manual page 54

The top tether anchors are located under the trim
covers on the rear seatback filler panel. Flip open
the trim cover to access the anchors. Be sure to use
an anchor located on the same side of the vehicle
as the seating position where the child restraint will
be placed.
54
To assist you in locating
the top tether anchors,
the top tether anchor
symbol is located on
the trim cover.
Do not secure a child restraint in the right front
passenger's position if a national or local law
requires that the top tether be attached, or if the
instructions that come with the child restraint
say that the top tether must be attached. There is
no place to attach the top tether in this position.
Accident statistics show that children are safer
if they are restrained in the rear rather than
the front seat. See Where to Put the Restraint on
page 50 for additional information.