Received: 9 June 2018
Accepted: 5 April 2019
First Online: 24 April 2019
: Prof. Mohamed Abo El AzayemProfessor and previous Head of Agricultural Economic Department, National Research Centre.Prof. Nagwa El AgroudyProfessor at Agricultural Economic Department, National Research Centre.Dr. Salah Said Abd el-GhaniResearcher at National Research Centre.Dr. Tamer Gamal Ibrahim MansourResearcher at National Research Centre.
: All participants in the study know the purpose and participated in it voluntarily.
: Not applicable.
: The authors declare that they have no competing interests.
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