Horváth G, Malik P, Kriska Gy et al: Ecological traps for dragonflies in ... (2007)

Horváth G, Malik P, Kriska Gy, Wildermuth H.
2007
Ecological traps for dragonflies in a cemetery: attraction of Sympetrum species (Odonata: Libellulidae) by horizontally polarizing black gravestones.
Freshwater Biology 52: pp. 1700–1709.