Maybe the document can be found in any of the CSIC libraries. You can first refer to the   CSIC Libraries network catalog  to check where that document can be found and request a copy.

If the document cannot be found among the CSIC documentary funds, the CSIC Libraries network can still assist you in locating it and getting a copy. At this website you will find the all the needed information about their services:

Http://bibliotecas.csic.es/reproduccion-de-documentos