9Mureh S J, KrishnaRaj S, Saxenapk. Tryptophan is a prepcursor for melatonin and serotonin biosythesis in vitro regenerated St. John's wort (Hypericum perforatum L. CV. Anthos)plants [J]. Plant Cell Reports, 2000, 19(7): 698-704.
10Murch S J, Haq K, Rupasinghe HPV, Nickel contamination affects growth and secondary metabolite composition of St. John's wort (Hypericum perforatum L,) [J]. Environmental and Experimental Botany, 2003, 49 ( 3 ): 251-257.