R. Fleischmajer, R. Timpl, L. Tuderman, L. Raisher, M. Wiestner, J. S. Perlish, P. N. Graves,
Ultrastructural identification of extension aminopropeptides of type I and III collagens in human skin Proceedings of the National Academy of Sciences of the United States of America. ,vol. 78, pp. 7360- 7364 ,(1981) ,
10.1073/PNAS.78.12.7360