You'll not find a definitive reference since the Glycemic Index is
manifestation of dubious science and poor statistical extrapolation.
You know, like Global Warming.

Taddy let's start with a simple apple. No, scratch that, this is a
LOW-carbohydrate support group.  Take a strawberry.  It contains
fructose, glucose and other sugars usually measured as degrees Brix or
Baumé when made into a liquid.  Depending on growing conditions such
as temperature, geography, microclimate, fertilization, soil
composition, species ( Fragaria virginiana in the USA or the European
Fragaria vesca, ) or even CO2 concentration, the measured sugars or
just plain Brix will vary greatly.  That is why vintners rely on Brix
measurement to provide a consistent wine sugar profile.

Did I just say CO2 concentration.  Here is a fascinating reference
showing that the Kyoto Protocol is Low-Carb.

http://www.ingentaconnect.com/content/jws/jsfa/2004/00000084/00000012/art00005

Least I digress, the "definitive reference" that you will have shelled
out good money for will contain a single line for strawberry: Glycemic
Index 38.  There you have it. A GI of 38.  But taddy, your strawberry
will statistically NOT have a GI of 38.  Could be 20 if it is
out-of-season and unripe, could be 65 if grown in a CO2 enriched
greenhouse and left to overripen.

Also did you frappe, whip, stir, blend, chew or swallow whole?  All
these factors determine how that single strawberry will affect your
glycemic response.

As well as how many you ate at a sitting.

As well as when you ate it in regards to exercise.

There can be a very long list of variables indeed.

Save your money and get the online [read free] versions.  Then take it
with a grain of salt.