Dimitrova, Elitsa
Kotzeva, Tatyana
Alexandrova-Karamanova, Anna
Funding for this research was provided by:
Ministry of Education and Science of Bulgaria
Article History
Received: 30 April 2020
Revised: 26 July 2020
Accepted: 15 September 2020
First Online: 17 October 2020
Compliance with ethical standards
:
: The authors declare that they have no conflicts of interest.
: Ethical approval to conduct the survey was obtained by the Ministry of Education and Science of Bulgaria.
: The study complies with the ethical standards for research with human participants as laid down in the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards.
: Participation in the study was anonymous and voluntary. Active consent was sought from school principals and parents. Only children whose parents gave their written informed consent participated in the study. All the survey procedures for each data collection cycle were documented and can be downloaded from ExternalRef removed.