Carsalesbase.com's figures and Matt Gasnier/BSCB's wholesale
figures are taken from Chooseauto.com.cn, which ultimately sources data from CAAM (China Association of Automobile Manufacturers). [Wholesale figures refer to the "delivery" stats I mentioned]. These are good for quick references, but as I said, CAAM has a history of being hoodwinked by some of its own members (it is an association of all kinds of auto manufacturers, not just cars) in the past with inflated figures. But, on the whole, CAAM is considered to be authoritative and quoted by most publications.
CPCA is now known as China Automobile Circulation Association Automobile Market Research Branch (quite a mouthful!) and is an association of passenger and commercial vehicle manufactures (including new energy). It is affiliated to China Automobile Dealers Association, and the purpose of this organization is market research and analysis for the benefit of both manufacturers and dealers (including import dealers). Unlike CAAM, it does not include two-wheeler manufacturers. What it publishes is more analytical in nature (research on specific market segments, graphs, trends, indices, that sort of thing) and seldom make-or-model specific (or grainy data). See http://www.cpcaauto.com/