Resources to ID gastropods

[Andreik]

In a short trip today I found some sort of Hyppochrenes (Rostellaria). Does anyone know some resources where I can read about differences between species of Hyppochrenes or gastropods in general? I know there are two volumes of Conchyliologie systématique et classification méthodique des coquilles but my french it's almost inexistent.

 

 

I found this in the NW part of Romania in eocene limestones (Priabonian if I remember well). Sorry for not having a scale for the picture, it was kinda unexpected, but it roughly two kilos.