For those who can read Spanish, this is, in my opinion, a must: "Cuestión nacional y autonomía obrera en Euskal Herria" was a short book that the Basque Worker Autonomy organization Zirikatu published collectively in 1989. Now it has been made available online:
Zirikatu (to bother, to pinch) was a short-lived Autonomist organization in the Basque Country, whose main declared goal was to help to guarantee that the grassroots nature of popular organizations remained that way. In the book, among other things, they make an appeal for the long tradition of worker councils (i.e. soviets) that are not directed by any vertical organization but truly democratic as the only way ahead for the much needed communist revolution.
Source: Agintea Hausten (via Borroka Garaia Da!)