I don't know if this issue has been posted before, but here goes.

I spoke to Ghorza gra-Bagol and started the Miscellaneous quest entitled "Bring the Last Scabbard of Akrash to Ghorza".

According to the wiki, I've visited and cleared both locations where this book is located (Fort Sungard Muster and Gallows Rock) collecting it in the process.

I must have sold it as I don't have it in my inventory or any of my owned houses. (Should this be allowed to happen if it is a limited-quantity quest item?)

Now when I activate the quest, the arrow indicates an inaccessible location somewhere below the floor of the lab of Farengar Secret-Fire in Dragonsreach.

Does this mean that this quest is unfinishable, or will the book appear randomly in the inventory of a vendor?

Thanks for any advice you have,

ne0ge0