Explanation:

- Commercial Banks: These are formal financial institutions providing credit to the agriculture sector, making them a part of institutional credit sources. They give loans based on the government's agricultural policies.

- NABARD (National Bank for Agriculture and Rural Development): This is a development bank focused on rural and agricultural finance, playing a role in the institutional credit network, supporting rural and agriculture development.

- Regional Bank: Also part of the institutional credit structure, regional rural banks provide credit to small and marginal farmers, among other rural financing.

- Traders: Often part of the informal, non-institutional sources, traders provide credit to farmers using informal arrangements. They extend credit generally without formal documentation, often against crop pledges.