I am looking for a citation for the interpolation algorithm used in the GeoEnrichment Service (e.g. this algorithm http://resources.arcgis.com/en/help/arcgis-rest-api/index.html#//02r30000021s000000)
I have found
and an older BAO reference
I was hoping to find a citation in the "primary" literature not trade literature. The primary literature I have found focuses on using boundaries to do the apportionment, not centroids. Plus I have not seen any Census Block literature, only Census Tracts.