Baby squirrels in attic

I could use some help with squirrels. I am on a job where the mother squirrel got hit by a car and has left babies in attic. I am estimating the babies are 3-4 weeks old. The house is built in such a way as portions of the attic are inaccessible and I am sure that is where the babies are. I have thought about trying to call them out but have never done that. Is there a good recording i could download? Babies have been motherless for about 24 hours. I sure could use some suggestions.
cheers
mike

I use my mouth to imitate the female, it is the short bark with the higher pitch whine, most will not be able to do that with their mouth. but what you can try is to do the bark. short not the long alert bark, or try the growl with your mouth, think back and try to do that little growl that the young do. mom is the same just alittle different. if they are young they will have very little fear factor to them, and any squirrel sound may pull them or at least get them to move so you can maybe see or hear them. you can also try one of those squirrel calls just do the short barks. also I kiss the palm of my hand to inmate the sound the young make when scared to get mom to pop her head out of a hole or run to me, or run to show me the hole if I can't find it. I have seen when I do this from the roof or in a attic trying to get mom's attention, that the young will sometimes come and look, may want to give it a try. hey you can always take mom and put her in a trap and place it in the attic for a day or 2. she won't mind or feel a thing and the young if close and if they are mobile, may smell her, and may come to her sometimes.

Sit and listen and have the homeowners listen. When you hear and pinpoint where they are, grab a keyhole saw and cut em out.