Standardised brick size and type particular to specific periods figure prominently as dating tools in South Asian excavation reports (too many to collate here). For example, tables based on brick size are provided in G. Verardi's (2007) Excavations at Gotihawa and Pipri, Kapilabastu District, Nepal, Rome, IsIAO.
Further, more general discussion:
T.N. Mishra, 1997
Ancient Indian bricks and Brick Remains, New Delhi: Harman
E.S.N. Reddy, 1998. Evolution of building technology: Early and Medieval in Andhradesa, 2 vols. New Delhi. Bharatiya Kala Praashan.
M. Pareek, 2002. Early Indian Residential architecture.
I'll try to look out some other references on continuities / discontinuities between Harappan / early-historic brick technology. There is also ethno-archaeological work on brick making communities, again which I'll need to look out.
Best wishes
Julia