Key points are not available for this paper at this time.
Katayoon Dehesh, Chris Franci, Brian M. Parks, Kevin A. Seeley, Timothy W. Short, James M. Tepperman, Peter H. Quail, Arabidopsis HY8 Locus Encodes Phytochrome A, The Plant Cell, Vol. 5, No. 9 (Sep., 1993), pp. 1081-1088
Dehesh et al. (1993) studied this question.