A kind of Utkālika Śruta (a category of Āgamas (canonical works), which is allowed to be studied at all time barring the akāla prahara (i.e., the period in which the study of Āgamas is prohibited));
in which there is the description of the temporal measurement of the prahara (a quarter part of the day or night).
maṃḍale-maṃḍale aṇṇoṇṇā porisī jattha ajjhayaṇe daṃsijjati tamajjhayaṇaṃ porisimaṃḍalaṃ.
(Nandī 77 Cū p. 58)