@article{
  author = {Saadat Mehr, Ayub ,  Dastmard, Zakia},
  title = {Analysis of the content of Persian books in the second half of the elementary school (sixth grade)},
  journal = { Environmental sciences and geography knowledge},
  year = {2021},
  volume = {1},
  number = {2},
  pages = {-},
  doi = {}
}