Filolog.

The language of the oldest runic inscriptions / È. A. Makaev. - Stockholm, 1996.

PN-ISO 9

Istoriko-tipologičeskaâ morfologiâ germanskih âzykov : kategoriâ glagola / redakcionnaâ kollegiâ M. M. Guhman, È. A. Makaev, V. N. Ârceva. - Moskva, 1977.

RNB online

ru.wikipedia, 19.07.2018 https://ru.wikipedia.org/wiki/%D0%9C%D0%B0%D0%BA%D0%B0%D0%B5%D0%B2,_%D0%AD%D0%BD%D0%B2%D0%B5%D1%80_%D0%90%D1%85%D0%BC%D0%B5%D0%B4%D0%BE%D0%B2%D0%B8%D1%87