Malaclypse the Young - Principia Discordia - paperback or softback - X555z

Newton - Principia - New paperback or softback - X555z

Smith - Principia Latina - paperback or softback - X555z

Home - Principia Medecinae... - paperback or softback - X555z

Grau - Principia Cognitionis Humanae - paperback or softback - X555z

Anonymous - German Principia Part 1 - paperback or softback - X555z

Anonymous - French Principia Part 1 - paperback or softback - X555z

Whitehead - Principia Mathematica Volume One - paperback or softback - X555z