This is beautiful butterfly design named as Alexander swallowtail butterfly.This design is created by Michael LaFosse.
Complexity :-
On complexity level it is intermediate.
Paper used:-
Normal Origami sheets of 4.5 Inches Square
Book:-
Michael LaFosse’s book – Origami Butterflies
Instruction:-
The best place to learn this model is at Michael LaFosses website PEM Origami.It is a 17.51 minutes video.Click on fold more models > In list of 2007 you can find the instruction link for butterfly.