diff --git a/gtfs/spec/en/reference.md b/gtfs/spec/en/reference.md
index 7a9b1058..15838fed 100644
--- a/gtfs/spec/en/reference.md
+++ b/gtfs/spec/en/reference.md
@@ -407,14 +407,14 @@ File: **Optional**
 
 Primary Key (`fare_product_id`, `fare_media_id`)
 
-To describe the different types of tickets or fares that can be purchased by riders.
+Used to describe the range of fares available for purchase by riders or taken into account when computing the total fare for journeys with multiple legs, such as transfer costs.
 
 |  Field Name | Type | Presence | Description |
 |  ------ | ------ | ------ | ------ |
-| `fare_product_id` | ID | **Required** | Identifies a fare product. |
+| `fare_product_id` | ID | **Required** | Identifies a fare product or set of fare products.<br><br>Multiple records in [fare_products.txt](#fare_productstxt) may share the same `fare_product_id`, in which case all records with that ID will be retrieved when referenced from another file.<br><br>Multiple records may share the same `fare_product_id` but with different `fare_media_id`s, indicating various methods available for employing the fare product, potentially at different prices. |
 | `fare_product_name` | Text | Optional | The name of the fare product as displayed to riders. |
 |  `fare_media_id` | Foreign ID referencing `fare_media.fare_media_id` | Optional |  Identifies a fare media that can be employed to use the fare product during the trip. When `fare_media_id` is empty, it is considered that the fare media is unknown.|
-| `amount` | Currency amount | **Required** | The cost of the fare product. May be negative to represent transfer discounts. May be zero to represent a fare product that is free.|
+| `amount` | Currency amount | **Required** | The cost of the fare product. May be negative to represent transfer discounts. May be zero to represent a fare product that is free. |
 | `currency` | Currency code | **Required** | The currency of the cost of the fare product. |