1. Hypericin in the Light and in the Dark: Two Sides of the Same Coin
   Zuzana Jendželovská et al, 2016, Front. Plant Sci. CrossRef
2. Three-dimensional in vitro cancer spheroid models for photodynamic therapy: strengths and opportunities
   Conor L. Evans, 2015, Front. Phys. CrossRef
3. Topically applied hypericin exhibits skin penetrability on nude mice
   Zhuo-heng Li et al, 2018, Lasers Med Sci CrossRef