- Lafranchis, T. (2009) Dagvlinders van Europa. KNNV Uitgeverij, Zeist.
- All* butterflies are caught with a specific insect net.
- They are tranferred to a petridish, whereafter photographs are taken from the upper and under parts.
- Thereafter, the butterfly is released.
- Photo’s are stored in a database.
- Observations are uploaded to Hatikka.fi
* Of easy reckognizable species (e.g. L. virguareae, A. hyperanthus, etc) only a few individuals are caught and photographed.