id	domain	url
alkej-224	en.wikipedia.org	http://en.wikipedia.org/wiki/chemical_element
alkej-224	en.wikipedia.org	http://en.wikipedia.org/wiki/characterization_(materials_science
alkej-224	en.wikipedia.org	http://en.wikipedia.org/wiki/x-ray
alkej-224	en.wikipedia.org	http://en.wikipedia.org/wiki/atom
alkej-224	en.wikipedia.org	http://en.wikipedia.org/wiki/electron
alkej-224	en.wikipedia.org	http://en.wikipedia.org/wiki/proton
alkej-224	books.google.com	http://books.google.com/books?id=ruf9dqxcdlqc
alkej-224	books.google.com	http://books.google.com/books?id=ruf9dqxcdlqc
alkej-224	en.wikipedia.org	http://en.wikipedia.org/wiki/international_standard_book_number
alkej-224	en.wikipedia.org	http://en.wikipedia.org/wiki/special:booksources/978-0-306-47292-3