Orawan Orostrairat. 1993. The role of honey bees, ceratinini bees and stingless bee on sunflower (Helianthus annuus L.) pollination. Bangkok:Kasetsart University;
Orawan Orostrairat. (1993) The role of honey bees, ceratinini bees and stingless bee on sunflower (Helianthus annuus L.) pollination (รายงานผลงานวิจัย). Kasetsart University:Bangkok.
Orawan Orostrairat. The role of honey bees, ceratinini bees and stingless bee on sunflower (Helianthus annuus L.) pollination. Bangkok:Kasetsart University, 1993.
Orawan Orostrairat. (1993) The role of honey bees, ceratinini bees and stingless bee on sunflower (Helianthus annuus L.) pollination (รายงานผลงานวิจัย). Kasetsart University:Bangkok.