translate English to French: However, even the extended deﬁnitions did not lead to a stable moneydemand function, probably because the added components are not completely transactions-oriented, but also include some money held as a liquid store of value.
Un modèle doté de paramètres variables dans le temps et faisant appel à un ﬁltre de Kalman pourrait sembler approprié, mais son estimation s’est révélée difﬁcile à cause de la petite taille de l’échantillon.