I presume you mean Bolognese
, that is, a ragù in the style of Bologna. Ah, Bologna la grassa
-- Bologna the fat, quite a good distance from the French border, actually -- of which it is said: "Every proper Bolognese [person who comes from Bologna] is secure in his or her own formula for constructing this most fundamental Emilian sauce, each of them holding tightly to an inviolable and sacred method." Veal, pork, porcini, milk, cream, tomato, carrots: Yes? No? Never? Don't be ridiculous. Especially if you, like me, are an American not even distantly related to Italia.
In other words, no matter what you or I or anyone can find in a book, there is no absolute version of any recipe. Oh, sure, there's la ricetta ufficiale della Camera di Commercio Industria Artigianato e Agricoltura di Bologna
which -- ahem -- includes cream or milk. But does that mean it is the only way it will be done? Nonsense. So all of these "Oh that should NEVER include cream" or "That ALWAYS has egg yolks" is just trying to show off that you have a book you can quote. But it does not prove anything other than you can read. Maybe.