A. Pietrowski
发表
A. Karrass,
D. Solitar,
A. Pietrowski,
1974,
Canadian Journal of Mathematics.
A. Pietrowski,
J. McCool,
1973
.
M. J. Dunwoody,
A. Pietrowski,
1973,
Canadian Mathematical Bulletin.
A. Karrass,
D. Solitar,
A. Karrass,
1973,
Journal of the Australian Mathematical Society.