I James, E
Thomas, An approach to the enumeration problem for
non-stable vector bundles, J. Math. Mech. 14 (1965)
485–506 MR0175134
3
R C Kirby, P
Melvin, P Teichner, Cohomotopy sets of
4–manifolds, from: "Proceedings of the FreedmanFest"
(editors V Krushkal, R Kirby, S Wang), Geom. Topol. Monogr. 18
(2012) 161–190
4
L L Larmore, E
Thomas, Group extensions and principal fibrations,
Math. Scand. 30 (1972) 227–248 MR0328935
F P Peterson,
E Thomas, A note on non-stable cohomology
operations, Bol. Soc. Mat. Mexicana 3 (1958) 13–18
MR0105680
9
L Pontrjagin, A
classification of mappings of the three-dimensional complex
into the two-dimensional sphere, Rec. Math. [Mat. Sbornik]
N. S. 9 (51) (1941) 331–363 MR0004780