Guilletta
Have not been back online since yesterday, but have checked, the best book I have read on the subject of bilingual upbringing is this one
I liked that she offered alternatives to the OPOL method. I found it very interesting and informative.
The other book that I read was this one, which was ok, but a bit repetitive. Both books look into other methods than OPOL.
As far as I can remember, Elke Montanari writes about which is the dominant language. I have loaned the book to our kindergarten teacher so cannot look it up at the moment.