**Barth (2012) 210 Cal.App.4th 363** Trial court can establish child support retroactive to petition per Cal. Fam. Code § 4009. <!-- citation-library:start --> ## Citation reference Barth, In re Marriage of (2012) 210 Cal.App.4th 363, 147 Cal.Rptr.3d 910 > [!info] Working notes > This is a personal working note. Citation details are for reference; opinion and current-status verification may still be pending. <!-- citation-library:end -->