[Ancilli 1983]60
[De Pablo Maroto 1965]
[Gruijs 1976]106-107
[Hogg 1984a][Hogg 2006d]
[Krynen 1964]
[Malm 2011a][Martin 1996][Mertens 1984][Mertens 1985][Miquel 1985]157-160
NBC 2005b, beelden 90-92[Nyberg 2002]
[Ruello 1981]
[Schepers 1994]
[Trottmann 2010]
[Vial 2009]
[Walach 2009]
