1. Ss. Cyril and Methodius University in Skopje, Skopje, Macedonia
2. Wageningen University & Research Animal Breeding and Genomics, Wageningen, The Netherlands
3. Institute for Bee Research Hohen Neuendorf, Hohen Neuendorf, Germany
4. Landesbetrieb Landwirtschaft Hessen, Bieneninstitut, Germany