"Väktare" (Guardian), sculpture, Berengo Studio, Murano, Italy 2000, ed 2/6
Four mallards in multi-coloured glass, signed BILLGREN 2/6, height 44.3 cm.
Liljevalchs, Stockholm, 'Ernst Billgren', 28th of October - 7th of January 2001.
Carl Johan de Geer, 'Ernst Billgren', 2000, compare the model ill. p 163.