From a syntactic source.
The compound verb e)pidokima/zw [see delta 1327, delta 1328 for the simple dokima/zw] is so rare as to merit no entry in LSJ. Besides here, it is attested only once, in a quotation from Isocrates 2 (To Nicocles) 28 in the Anthology of Joannes Stobaeus, with the present participle e)pidokima/zontas. The transmitted text of Isocrates, however, has there the future participle of a different (and somewhat more common) compound, sundokima/sontas.