1. Avery, O.T., MacLeod, C.M. and McCarty, M. (1944) Studies on the chemical nature of the substance inducing transformation of pneumococcal types. J. Exp. Med. 79, 137–157.
2. Björn, L.O. (1969a) Action spectra for transformation and fluorescence of protochlorophyll holochrome from bean leaves. Physiol. Plant. 22, 1–17.
3. Björn, L.O. (1969b) Studies on the phototransformation and fluorescence of protochlorophyll holochrome in vitro. In H. Metzner (Ed.), Progress in photosynthesis research, Vol. II, pp. 618–629. H. Laupp Jr., Tübingen, Germany.
4. Björn, L.O., Sundqvist, C., and Öquist, G. (2007) A tribute to Per Halldal (1922–1986), a Norwegian photobiologist in Sweden. Photosynthesis Res. 92, 7–11.
5. Diakoff, S. and Scheibe, J. (1973) Action spectra for chromatic adaptation in Tolypothrix tenuis. Plant Physiol. 51, 382–385.