@article{articleadb438d0,
title   = {Yttrium oxysulfide nanosized spherical particles doped with Yb and Er or Yb and Tm: efficiency materials for up-converting phosphor technology field},
author = {Pires, Ana Maria and Serra, Osvaldo Antonio and Davolos, Marian Rosaly},
year = {2004},
doi = {10.1016/j.jallcom.2003.11.088},
journal   = {Journal of Alloys and Compounds}
}