Klāvs Siliņš: Latviešu personvārdu vārdnīca. Riga "Zinātne" 1990, ISBN 5-7966-0278-0
Population Register of Latvia: Justīne was the only given name of 713 persons in Latvia on May 21st 2010.
Etymology
First recorded as a given name of Latvians in 1819. From LatinIustina, name of early saints, feminine of Iustinus, derivative of Iustus, from iustus(“just”). Cognate with French and English Justine.