For spaniards names.

A spaniard has a given name that sometimes is two (even more) like Pedro, Pablo, Juan Luis, María Eugenia, etc. The second given name is recognized because it is usually different from the usual given names. It is possible to have a family names like Carlos, but it is not quite frequent.

Additionally all the people has two family names, the first comes from the father's family and the second from mother's the family. Roughly this second family name works as the "middle initial" in some English speaking countries.

So, a mathematician named José Luis García Pérez should be cited like

García Pérez, José L.

In real life you might call him José, José Luis, or perhaps Pepe.

A really brief way and of course correct of referring to him is

García, J. L.

He might be tired of explains this subtleties to editors and authors and write his name as José Luis García-Pérez, avoiding references to him as prof. Pérez instead of the right prof. García. But this solution is not really compatible with the legal use stablished in Spain.

It happens that some people have complicated family names like Francisco Javier de la Vega Martínez, then the citation should be

Vega Martínez, Francisco J. de la

and the short version

Vega, F. de la

Another source of possible confusion is people with composite last names like, say Pedro Antonio García-Valcárcel Rodríguez. Then the composite works a single last name and most of the time its is not abbreviated. Perhaps in a desperate situation the first of the two because it usually is the more common. A citation should read

García-Valcárcel Rodríguez, Pedro A.

and the (extra) short version

G.-Valcárcel, P.

I think I am covering the several cases. Now for the extremely complicated example in the question: Juan Pablo Fernández de Calderón García-Iglesias. The name "Juan" is the first given name, thus the main one, "Pablo" is the second given name, "Fernández de Calderón" is the first last name, so the main one and "García-Iglesias" is a composite second last name. The right way of citation:

Fernández de Calderón García-Iglesias, Juan P.

a short version

Fernández de Calderón, J.

And if you are really out of space the following

Fdez. de Calderón, J.

would be possible. There are other variants but I think I've covered the key points.

For spaniards names.

A spaniard has a given name that sometimes is two (even more) like Pedro, Pablo, Juan Luis, María Eugenia, etc. The second given name is recognized because it is usually different from the usual family names. It is possible to have a family names like Carlos, but it is not quite frequent.

Additionally all the people has two family names, the first comes from the father's family and the second from mother's the family. Roughly this second family name works as the "middle initial" in some English speaking countries.

So, a mathematician named José Luis García Pérez should be cited like

García Pérez, José L.

In real life you might call him José, José Luis, or perhaps Pepe.

A really brief way and of course correct of referring to him is

García, J. L.

He might be tired of explaining this subtleties to editors and authors and write his name as José Luis García-Pérez, avoiding references to him as prof. Pérez instead of the correct prof. García. But this solution is not really compatible with the legal use stablished in Spain.

It happens that some people have complicated family names like Francisco Javier de la Vega Martínez, then the citation should be

Vega Martínez, Francisco J. de la

and the short version

Vega, F. de la

Another source of possible confusion is people with composite last names like, say Pedro Antonio García-Valcárcel Rodríguez. Then the composite works a single last name and most of the time its is not abbreviated. Perhaps in a desperate situation one might out an abbreviation for the first of the two because it is usually the more common. A citation should read

García-Valcárcel Rodríguez, Pedro A.

and the (extra) short version

G.-Valcárcel, P.

I think I am covering the several cases. Now for the extremely complicated example in the question: Juan Pablo Fernández de Calderón García-Iglesias. The name "Juan" is the first given name, thus the main one, "Pablo" is the second given name, "Fernández de Calderón" is the first last name, so the main one and "García-Iglesias" is a composite second last name. The right way of citation:

Fernández de Calderón García-Iglesias, Juan P.

a short version

Fernández de Calderón, J.

And if you are really out of space the following

Fdez. de Calderón, J.

would be possible. There are other variants but I think I've covered the key points.