test.bib

@article{larsson2018eulerr,
  title={eulerr: area-proportional Euler diagrams with ellipses},
  author={Larsson, Johan},
  year={2018}
}

@Book{ssa,
    author = {Hadley Wickham},
    title = {ggplot2: Elegant Graphics for Data Analysis},
    publisher = {Springer-Verlag New York},
    year = {2016},
    isbn = {978-3-319-24277-4},
    url = {https://ggplot2.tidyverse.org},
  }
  
@Manual{sss,
    title = {gridExtra: Miscellaneous Functions for "Grid" Graphics},
    author = {Baptiste Auguie},
    year = {2017},
    note = {R package version 2.3},
    url = {https://CRAN.R-project.org/package=gridExtra},
  }
  
@Manual{ggplotpackage,
    title = {ggplot2: Create Elegant Data Visualisations Using the Grammar of Graphics},
    author = {Hadley Wickham and Winston Chang and Lionel Henry and Thomas Lin Pedersen and Kohske Takahashi and Claus Wilke and Kara Woo and Hiroaki Yutani and Dewey Dunnington},
    year = {2023},
    note = {R package version 3.4.4},
    url = {https://CRAN.R-project.org/package=ggplot2},
  }
  
@Book{bookgreek,
    author = {Stylianos Andreadakis and Vasileios  Katsargyris and Stefanos Metis and Konstantinos Brouchoutas and Stavros Papastavridis and Georgios Polyzos},
    title = {Marhematics of Third grade (Student's Book - High School) - Part II},
    publisher = {CTI - Diophantus},
    year = {2021},
    url = {http://ebooks.edu.gr/ebooks/v/html/8547/2732/Mathimatika_Teuxos-B_G-Lykeiou-ThSp_html-apli/index.html},
  }
  
  @Book{bookgreek2,
    author = {Stylianos Andreadakis and Vasileios  Katsargyris and Stavros Papastavridis and Georgios Polyzos and Andreas Sverkos and L Adamopoulos and X Damianou},
    title = {Algebra and elements of probability (Student's Book - First Grade of High School)},
    publisher = {CTI - Diophantus},
    year = {2022},
    url = {http://ebooks.edu.gr/ebooks/v/html/8547/2732/Mathimatika_Teuxos-B_G-Lykeiou-ThSp_html-apli/index.html},
  }