I have not used this recipe, I found it in a book I have.

Sourdough Bread

1 cup starter (see below)
2 TBSP margarine or butter
2 TBSP sugar
1 1/2 tsp salt
3 cups bread flour
1 1/2 tsp yeast
1/4 - 2/3 cup milk (adjust consistency of dough with milk while the dough is kneading)

starter: mix together:
2 cups lukewarm milk
2 cups bread flour
2 1/2 tsp (1 package) yeast
Cover & place in a warm, draft-free location for 4 to 7 days, gently stirring it once a day. If mixture bubbles &/or overflows the bowl it means you have a healthy fermenting process going on. A sour smelling liquid may form on top of the starter which should be stirred back in.
*If starter changes colors, to purple, for example, it should be discarded.
After allowing the starter to sit for 4-7 days, it is ready to be used. Take out whatever portion your recipe calls for & put it into the machine as you would any liquid ingredient. After removing a portion from the starter, what is left must be "fed". Add equal portions of milk or water & flour as was used. For example, is you used 1 cup of starter, replace with 1 cup of milk & 1 cup of bread flour. Alternate between milk & water for each feeding. After feeding the starter, let it sit at room temperature for 1 day & then refrigerate.