[1] Vonage の開発スタートガイド, https://zenn.dev/kwcplus/articles/vonage-start-guide
[2] Technical Details, https://developer.vonage.com/en/account/technical-details?source=account
[3] Vonage SMS ガイド, https://zenn.dev/kwcplus/articles/vonage-sms-guide
[4] SMS Delivery Receipts API Guide| Vonage API Documentation, https://developer.vonage.com/en/messaging/sms/guides/delivery-receipts
[5] Vonage Olympus API (v1.0) Reference | Vonage API Documentation, https://developer.vonage.com/en/api/messages-olympus?source=messages
[6] Webhooks, https://developer.vonage.com/en/getting-started/concepts/webhooks
[7] 連結とエンコード, https://developer.vonage.com/ja/messaging/sms/guides/concatenation-and-encoding