Source of Induced Drag

A couple of recently read articles described different sources for
induced drag.

One attributed the drag to the wingtip vortices ... increased angle of
attack created bigger vortices.

Another said the drag was the result of the lift vector tilting
backwards at higher angles of attack ... creating a rearward 'induced
drag' resultant.

I have heard the tip vortex explanation before ... the induced drag
vector seems plausible ... does it have any merit.

If induced drag is a result of both of these effects ... what is the
relative weight of each?

gracias'

KK