A network for historic guitars and vihuelas
I don't know if it is the complete work, but a reprint was published by Minkoff in1981, which you may be able to find. It contains a title page, six more pages and a page of tunings, examples, etc. for the bandurria. For the cittern (cithara con trastes), there is only most of one page, where the partially fretted cittern is deliberately excluded. The cittern (citara) tuning given has the third course raised a tone from g to a, which differs from England, Italy and the Low Countries of course. The 'music' page is shared with a keyboard's and gives a list of chords and another which gives guitar alfabeto equivalents.
I don't know that there is not another book? Let me know if you are unable to find this edition and I can help in any way.