[Skiascopic rulers with convexo-concave ("nonastigmatic") lenses].

@article{Krasnikov1979SkiascopicRW,
  title={[Skiascopic rulers with convexo-concave ("nonastigmatic") lenses].},
  author={P G Krasnikov},
  journal={Oftalmologicheskii zhurnal},
  year={1979},
  volume={34 7},
  pages={441-2}
}