Tsegay, B. A., L. Lund, J. Nilsen, J. E. Olsen, J. M. Molmann, A. Ernsten, and O. Juntttila. “Growth Responses of Betula Pendula Ecotypes to Red and Far-Red Light”. Electronic Journal of Biotechnology, vol. 8, no. 1, Apr. 2005, pp. 0-0, https://preprints.pucv.cl/index.php/ejbiotechnology/article/view/v8n1-10.