diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md
index 0394761ad..39238848c 100644
--- a/specs/core/0_beacon-chain.md
+++ b/specs/core/0_beacon-chain.md
@@ -1642,7 +1642,7 @@ For every `slot in range(state.slot - 2 * EPOCH_LENGTH, state.slot)`, let `cross
 
 Define the following helpers to process attestation inclusion rewards and inclusion distance reward/penalty. For every attestation `a` in `previous_epoch_attestations`:
 
-* Let `inclusion_slot(state, index) = a.slot_included` for the attestation `a` where `index` is in `get_attestation_participants(state, a.data, a.aggregation_bitfield)`.
+* Let `inclusion_slot(state, index) = a.slot_included` for the attestation `a` where `index` is in `get_attestation_participants(state, a.data, a.aggregation_bitfield)`. If multiple attestations are applicable, the attestation with lowest `slot_included` is considered.
 * Let `inclusion_distance(state, index) = a.slot_included - a.data.slot` where `a` is the above attestation.
 
 ### Eth1 data