Type-I non-critically phase-matched second-harmonic generation in Gd1-xYxCa4O(BO3)3 - Burmester, P.B.W.; Kellner, T.; Petermann, K.; Huber, G.; Uecker, R.; Reiche, P. (Springer, 1999)
http://dx.doi.org/10.1007/s003400050758
Keywords: U