I have been baking with Dak machines for several years.  In fact, I
currently own the orginal Dak Auto Bakery and the newer Turbo Baker IV.
I think they are wonderful.
I also bought Turbo Baker II but was not satisfied with it.  I
returned it and received a full refund from Dak.) 
Of the many bread machines books I have used, I like the 4-volume
set by Donna German best (especially Volume 3).  I developed my own 
sourdough recipes that produced very good results but switched to 
her recipes; they involve less work and they also produce very good 
sourdough bread.
Here is another nice and simple sourdough recipe.  It appears in a 
booklet sent by Dak to purchasers of the Turbo IV.  I used ordinary
bread flour, the "Oat/French" setting, and the regular (4 hour) cycle.  
The booklet states that the shorter turbo cycle also works.
    Sourdough Bread (from Dak for Turbo Baker IV)
    1 package yeast
    3 cups Better for Bread white flour
    1 teaspoon salt
    1 teaspoon sugar
    1 cup water (very warm)
    1 cup sourdough starter
    Add ingredients in the order listed.
    Select either "White" or "Oat/French" setting and turn
    the brown control to darkest setting.
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Murray Kirch
mrk@vax002.stockton.edu
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