1. Yearly report of the Uppsala observatory, Upsala universitets årsskrift 1893 69 74
2. For information on the societies' early activities, see Fotografisk tidskrifts årsbok 1894–95 80ff. 80ff. and vols 1–5 (1888–92) of Fotografisk tidskrift. The scientists made significant contributions to the activities in the photographic societies. See, for example, Nils Dunér's survey of the relative merits of 124 recipes for developers, in Fotografisk tidskrift, vols 3 and 4 (1890–91).