Greilhuber , J , Ebert , I , Lorenz , A & Vyskot , B 2000 , ' Origin of facultative heterochromatin in the endosperm of Gagea lutea (Liliaceae) ' , Protoplasma , vol. 212 , no. 3-4 , pp. 217-226 . https://doi.org/10.1007/BF01282922