@article{DAN_1967_172_2_a15,
     author = {B. V. Ershov and Yu. P. Pimenov and A. M. Prokhorov and V. B. Fedorov},
     title = {Two-photon absorption in the $\mathrm{CaF}_2:\mathrm{Ho}^{3+}$ crystal},
     journal = {Doklady Akademii Nauk},
     pages = {309--312},
     publisher = {mathdoc},
     volume = {172},
     number = {2},
     year = {1967},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1967_172_2_a15/}
}