"Singularities of 2-spheres in 4-space" by Fox and Milnor. Ten pages which generated hundreds of papers in knot theory.

http://projecteuclid.org/DPubS?service=UI&version=1.0&verb=Display&handle=euclid.ojm/1200691730

"Singularities of 2-spheres in 4-space and cobordism of knots" by Fox and Milnor. Ten pages which generated hundreds of papers in knot theory.

https://projecteuclid.org/journals/osaka-journal-of-mathematics/volume-3/issue-2/Singularities-of-2-spheres-in-4-space-and-cobordism-of/ojm/1200691730.full