BibTex format
@article{Chaplain:2020:10.1103/PhysRevB.101.155430,
author = {Chaplain, GJ and Craster, R},
doi = {10.1103/PhysRevB.101.155430},
journal = {Physical Review B: Condensed Matter and Materials Physics},
pages = {155430 1--155430 9},
title = {Ultrathin entirely flat Umklapp lenses},
url = {http://dx.doi.org/10.1103/PhysRevB.101.155430},
volume = {101},
year = {2020}
}