diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md
index 3192baa335..aa968722e7 100644
--- a/specs/core/0_beacon-chain.md
+++ b/specs/core/0_beacon-chain.md
@@ -1368,14 +1368,16 @@ All [validators](#dfn-validator):
 
 * Let `this_epoch_attestations = [a for a in state.latest_attestations if state.slot - EPOCH_LENGTH <= a.data.slot < state.slot]`. (Note: this is the set of attestations of slots in the epoch `state.slot-EPOCH_LENGTH...state.slot-1`, _not_ attestations that got included in the chain during the epoch `state.slot-EPOCH_LENGTH...state.slot-1`.)
 * Let `this_epoch_boundary_attestations = [a for a in this_epoch_attestations if a.data.epoch_boundary_hash == get_block_hash(state, state.slot-EPOCH_LENGTH) and a.justified_slot == state.justified_slot]`.
-* Let `this_epoch_boundary_attesters` be the union of the [validator](#dfn-validator) index sets given by `[get_attestation_participants(state, a.data, a.participation_bitfield) for a in this_epoch_boundary_attestations]`.
+* Let `this_epoch_boundary_attester_indices` be the union of the [validator](#dfn-validator) index sets given by `[get_attestation_participants(state, a.data, a.participation_bitfield) for a in this_epoch_boundary_attestations]`.
+* Let `this_epoch_boundary_attesters = [state.validator_registry[i] for indices in this_epoch_boundary_attester_indices for i in indices]`.
 * Let `this_epoch_boundary_attesting_balance = sum([get_effective_balance(v) for v in this_epoch_boundary_attesters])`.
 
 [Validators](#dfn-Validator) justifying the epoch boundary block at the start of the previous epoch:
 
 * Let `previous_epoch_attestations = [a for a in state.latest_attestations if state.slot - 2 * EPOCH_LENGTH <= a.slot < state.slot - EPOCH_LENGTH]`.
 * Let `previous_epoch_boundary_attestations = [a for a in this_epoch_attestations + previous_epoch_attestations if a.epoch_boundary_hash == get_block_hash(state, state.slot - 2 * EPOCH_LENGTH) and a.justified_slot == state.previous_justified_slot]`.
-* Let `previous_epoch_boundary_attesters` be the union of the validator index sets given by `[get_attestation_participants(state, a.data, a.participation_bitfield) for a in previous_epoch_boundary_attestations]`.
+* Let `previous_epoch_boundary_attester_indices` be the union of the validator index sets given by `[get_attestation_participants(state, a.data, a.participation_bitfield) for a in previous_epoch_boundary_attestations]`.
+* Let `previous_epoch_boundary_attesters = [state.validator_registry[i] for indices in previous_epoch_boundary_attester_indices for i in indices]`.
 * Let `previous_epoch_boundary_attesting_balance = sum([get_effective_balance(v) for v in previous_epoch_boundary_attesters])`.
 
 For every `shard_committee` in `state.shard_committees_at_slots`: