diff --git a/usbh_midi.cpp b/usbh_midi.cpp
index df2672cc..4de21770 100644
--- a/usbh_midi.cpp
+++ b/usbh_midi.cpp
@@ -148,6 +148,7 @@ uint8_t USBH_MIDI::Init(uint8_t parent, uint8_t port, bool lowspeed)
         p->lowspeed = lowspeed;
 
         // First Device Descriptor Request (Initially first 8 bytes)
+        // https://techcommunity.microsoft.com/t5/microsoft-usb-blog/how-does-usb-stack-enumerate-a-device/ba-p/270685#_First_Device_Descriptor
         rcode = pUsb->getDevDescr( 0, 0, 8, (uint8_t*)buf );
 
         // Restore p->epinfo