I don't know about what's on the internet but here are two books i can recommand you :
this one is showing erotic press from 1900 to post world war one. it's not very perverse or pornographic stuff, but beautiful works as well.
and i can't remember the title of the second one but it's containing hard pornographic stuff from the very begining of the 20th century, maybe even before. it's beautiful. i will look for it. but it's very expensive.