How do I find?

My Dad and Aunt were given up to a Children's Home in the early 30's.  They were twins.  How would I go about finding a "roster" of children in homes to find out where they might have been?  We know the general area, we think, in California. We are at a total loss as to how to do this.  They were at some point separated and we found a newspaper article stating that my Dad and two other boys ran away from one home they were in as teens.  Contacting that home has gotten us no where.  Thanks for any ideas

Lora