Tangential homotopy equivalences. I. Madsen, L.R. Taylor, B. Williams (1980) Commentarii mathematici Helvetici
Tetrahedra on deformed spheres and integral group cohomology. Blagojević, Pavle V.M., Ziegler, Günter M. (2009) The Electronic Journal of Combinatorics [electronic only]
The incidence submanifold of R P n × G 1 ( R P n ) for n odd is nonorientable Eugen Ružický (1976) Mathematica Slovaca