Bread-Bakers v100.n013.2

Can anyone tell me where I can buy Xanthum gum or Guar gum used in some
non-wheat bread recipes in B. Ojakangas book, "Whole Grain Breads by 
machine or hand".  It is a wonderful book and I have a friend who is wheat 
intolerant and the book has several non-wheat breads all of which call for 
one of these gums, but no source is listed.

Thanks.

--- Florence Moore
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