ἕστασαν

[Lavrentivs]

is apparently Doric for εἱστήκεσαν. Strange that North uses it? Anyway, I can't find the rest of the paradigm. ἕστασα yields no result as Perseus.

[Damoetas]

It's used in Attic also. ἵστημι is one of several verbs that have athematic forms in the perfect system, particularly in the plural. So, alongside the perfect ἑστήκαμεν, ἑστήκατε, and ἑστήκασιν, you also see ἕσταμεν, ἕστατε, ἑστᾶσι; and in the pluperfect, in addition to εἱστήκεμεν, εἱστήκετε, εἱστήκεσαν, there is ἕσταμεν, ἕστατε, ἕστασαν (even though some of these are identical to the perfect forms).

τέθνηκα and δέδοικα also have plurals in τέθναμεν and δέδιμεν, etc.

[Lavrentivs]

Thanks. Didn't see any reference to this in Smyth. Did I overlook it?

[Damoetas]

It's in Smyth 417 (the paradigm of ἵστημι) and discussed briefly in 762. Also, if you have Mastronarde's textbook, he talks about it in Unit 41. I just taught that chapter to my Greek class, so it was fresh in my mind!