Main contributions to the maps :

BDFMG (2011) (AP), Pesenko (in litt.).

Main collections studied (AP) : Belgium (Brussels, Gembloux, Mons); France (Paris).

Litterature: Friese (1897), Warncke (1976), Van der Zanden (1997), Baker (2002), Astafurova et Pesenko (2006).