P. Benedek, Economic importance of honey bee pollination of props at the national 12 level of Hungary, 29th International Apiculture Congress: Apimondia, pp.286-289, 1983.

R. Borneck and J. P. Bricout, Evaluation de l'incidence économique de l, p.14, 1984.

R. Borneck and B. Merle, Essai d'une évaluation de l'incidence économique de l'abeille 16 pollinisatrice dans l'agriculture européenne, Apiacta, vol.24, pp.33-38, 1989.

N. Carreck and I. Williams, The economic value of bees in the UK, Bee World, vol.11, issue.2, pp.115-133, 1998.
DOI : 10.1080/0005772X.1986.11098871

N. L. Carreck, I. H. Williams, and D. J. Little, The movement of honey bee colonies for crop pollination and honey production by beekeepers in Great Britain, Bee World, vol.110, issue.1, pp.67-77, 1997.
DOI : 10.1017/S0021859600078989

S. Naeem, R. V. O-'neill, J. Paruelo, and P. Raskin, The Value of 26 the world's ecosystem services, Nature, vol.387, pp.253-260, 1997.

A. Dag, I. Zipori, and Y. Pleser, Using bumblebees to improve almond pollination by the Ghazoul Recognizing the complexities of ecosystem management and the 12 ecosystem service concept, J, vol.16, pp.215-221, 2006.

S. S. Greenleaf and C. Kremen, Wild bees enhance honey bees' pollination of hybrid 14 sunflower, Proceedings of the National Academy of Sciences USA 103, pp.13890-13895, 2006.

D. Hassan and M. Simioni, Price Linkage and Transmission between Shippers and 16, 2001.

A. Klein, B. E. Vaissière, J. H. Cane, I. Steffan-dewenter, S. A. Cunnigham et al., Importance of pollinators in changing landscapes for world 19 crops, Proceedings of the Royal Society, pp.303-313, 2007.

C. Kremen, N. M. Williams, and R. W. Thorp, Crop pollination from native bees at risk 21 from agricultural intensification, Proceedings of the National Academy of Sciences USA 22 99, pp.16812-16816, 2002.

M. D. Levin, Value of bee pollination to United State agriculture, 1984.

J. E. Losey and M. Vaughan, The Economic Value of Ecological Services Provided by Insects, BioScience, vol.56, issue.4, pp.311-323, 2006.
DOI : 10.1641/0006-3568(2006)56[311:TEVOES]2.0.CO;2

E. C. Martin, The use of bees for crop pollination The 28 hive and the honey bee, In: Dadant & Sons, pp.579-614, 1975.

S. E. Mcgregor, Insect pollination of cultivated crop plants Agriculture Handbook, p.30, 1976.