The foundational text on labor time accounting, The Fundamental Principles of Communist Production and Distribution (1935), has now been published by Red & Black Books for free download. A printed edition is available, for example, from Syndikat-A.
In English, there is currently a 19-part podcast series about the Fundamental Principles.
The creators of the podcast have also announced plans to write a book about the Fundamental Principles and are seeking support. It certainly sounds exciting:
What was long dismissed as an impossible dream, we reveal to be both simple and elegant. (…) Planning is a continuous and distributed process. Communist theory must come to terms with this reality. Planning cannot be reduced to arbitrary time periods determined by administrative considerations. It must be a living, organic, democratic, and continuous process that follows only its own internal rhythm and the rational control of its participants.