The following books, among others, contain more information about Qvidja in Finnish and in Swedish:

Ahlbäck, Ragna (1946) Gods och herresäten i Finland. Söderström & Co, Helsinki.

Gardberg, C. J. and Dahl, Kaj (1989) Suomen kartanoita. Otava, Helsinki. Translated to Finnish by Irma Savolainen. In Swedish (1989) Finländska herrgårdar. Schildt, Helsinki.

Gardberg, C. J. and Welin, P. O. (1993) Suomen keskiaikaiset linnat. Otava, Helsinki. Translated to Finnish by Irma Savolainen. In Swedish (1993) Finlands medeltida borgar. Schildt, Helsinki.

Jutikkala, Eino and Nikander, Gabriel (1941) Suomen kartanot ja suurtilat II. Kivi, Helsinki.

Pargasbygdens historia I–IV (1955–1970) Pargas landskommun, Pargas köping & Pargasbygdens historiekommitté. (Especially part II (1959) with writing by  C. J. Gardberg ”Gråstensborgen på Qvidja”.)

Suistoranta, Kari (1985) Paraisten historia. Paraisten kaupunki, Parainen.

Qvidja on the Finna.fi website

Qvidja on the National Board of Antiquities website

Qvidja on the Finnish National Gallery website

In 2015, Qvidja was the subject of a building history report in Finnish, created by the Saatsi Arkkitehdit architect firm. The building history report contains more detailed information about Qvidja’s buildings and history.