According to Wikipedia, Even, S .; Itai, A .; Shamir, A. cited it in "On the complexity of time table and multi-commodity flow problems".
The paper can be found here: http://www.cs.technion.ac.il/users/wwwb/cgi-bin/tr-get.cgi/1975/CS/CS0059.pdf
EDIT: Reference [5] of the above paper can be found here: https://www.jstor.org/stable/2310460