diff --git a/gtfs/spec/en/reference.md b/gtfs/spec/en/reference.md
index 7fb9f4a9..a7261a1b 100644
--- a/gtfs/spec/en/reference.md
+++ b/gtfs/spec/en/reference.md
@@ -466,7 +466,7 @@ To process the cost of a leg:
| `from_timeframe_group_id` | Foreign ID referencing `timeframes.timeframe_group_id` | Optional | Defines the timeframe for the fare validation event at the start of the fare leg.
The “start time” of the fare leg is the time at which the event is scheduled to occur. For example, the time could be the scheduled departure time of a bus at the start of a fare leg where the rider boards and validates their fare. For the rule matching semantics below, the start time is computed in local time, as determined by [Local Time Semantics](#localtimesemantics) of [timeframes.txt](#timeframestxt). The stop or station of the fare leg’s departure event should be used for timezone resolution, where appropriate.
For a fare leg rule that specifies a `from_timeframe_group_id`, that rule will match a particular leg if there exists at least one record in `timeframes.txt` where all of the following conditions are true
- The value of `timeframe_group_id` is equal to the `from_timeframe_group_id` value.
- The set of days identified by the record’s `service_id` contains the “current day” of the fare leg’s start time.
- The “time-of-day” of the fare leg's start time is greater than or equal to the record’s `timeframes.start_time` value and less than the `timeframes.end_time` value.
An empty `fare_leg_rules.from_timeframe_group_id` indicates that the start time of the leg does not affect the matching of this rule. |
| `to_timeframe_group_id` | Foreign ID referencing `timeframes.timeframe_group_id` | Optional | Defines the timeframe for the fare validation event at the end of the fare leg.
The “end time” of the fare leg is the time at which the event is scheduled to occur. For example, the time could be the scheduled arrival time of a bus at the end of a fare leg where the rider gets off and validates their fare. For the rule matching semantics below, the end time is computed in local time, as determined by [Local Time Semantics](#localtimesemantics) of [timeframes.txt](#timeframestxt). The stop or station of the fare leg’s arrival event should be used for timezone resolution, where appropriate.
For a fare leg rule that specifies a `to_timeframe_group_id`, that rule will match a particular leg if there exists at least one record in `timeframes.txt` where all of the following conditions are true
- The value of `timeframe_group_id` is equal to the `to_timeframe_group_id` value.
- The set of days identified by the record’s `service_id` contains the “current day” of the fare leg’s end time.
- The “time-of-day” of the fare leg's end time is greater than or equal to the record’s `timeframes.start_time` value and less than the `timeframes.end_time` value.
An empty `fare_leg_rules.to_timeframe_group_id` indicates that the end time of the leg does not affect the matching of this rule. |
| `fare_product_id` | Foreign ID referencing `fare_products.fare_product_id` | **Required** | The fare product required to travel the leg. |
-| `rule_priority` | Non-negative integer | Optional | Defines the order of priority in which matching rules are applied to legs, allowing certain rules to take precedence over others. When multiple entries in `fare_leg_rules.txt` match, the rule or set of rules with the highest value for `rule_priority` will be selected.
An empty value for `rule_priority` is treated as zero. If the `rule_priority` field exists, it should not have all records entirely empty. |
+| `rule_priority` | Non-negative integer | Optional | Defines the order of priority in which matching rules are applied to legs, allowing certain rules to take precedence over others. When multiple entries in `fare_leg_rules.txt` match, the rule or set of rules with the highest value for `rule_priority` will be selected.
An empty value for `rule_priority` is treated as zero. |
### fare_transfer_rules.txt