This is a study by D. Goldberg, 1932.
White moves.

I never knew which result should be.

It is a draw in the original problem.

I considered one variation that was wrong, I explored it more deeply and found a very instructive and interesting way of winning a basic position.

 

I hope you can enjoy it. 

not really, because if white skips his turn, black can still mate white

calvinhobbesliker wrote: not really, because if white skips his turn, black can still mate white

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Of course black wins in the selected variation. I meant draw in the correct solving of the problem.

Black wins in that variation more quickly with 8. ... Qa7+ 9. Kg8 Kg6 and white has to give up the queen to prevent mate as in your line.

Loomis wrote:

Black wins in that variation more quickly with 8. ... Qa7+ 9. Kg8 Kg6 and white has to give up the queen to prevent mate as in your line.

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 To 8... Qa7+ white answer 9. Qg7 checks, and will be a draw.

Oh, good catch, thanks.