There is a website, checked it myself, but it might be too advanced for anyone to practice. Those spells were used in the dark ages, against kings of peace. I'll tell you, but i'll have to know why you want to learn this. Most spells are for Black Sorcerers, message me if you wish to know more.
Alrite, found some safe sites, not the Actual site i was talking about but, these sites can tell you some things. Im not going to post the REAL necromanic site, but these are the sites you can explore and more;
There is a link from the Library that goes abit deeper with this:
Necromancy is simply a path, a means to live as any magical options. Simply put, it involves traversing the roads of death and between, and being willing to accept that you will inevitably die. Prehaps sooner then a majority of paths studying necromancy causes a person to confront themselves, their egos and fears to evolve spiritually.