Since I didn't want to have anything to do with .xslx, I went for the pdf.
But later, when I told Mechatotoro about it, he entered the platform and gave "spreadsheet" a try.
"I love these people!," I heard him say.
Instead of a .xslx file, the guys who added the feature did honor the university's migration to free software and made .ods available for download!
And just a few minutes ago, my editor sent me an e-mail. Actually, the mail was directed to all the authors who work with her, and she wanted us to check the list of the available books and their corresponding prices to rule out any mistake.
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Yes! I literally heard a choir of angels singing. I am still hearing them! ^__^