[Yardley 1985]

Yardley, J. TSX-Plus: A Multiuser Operating System for the LSI-11 and PDP-11. MP&MS, Vol. 9, No. 5, June 1985, pp. 253-257.

[Yourdon 1979]

Yourdon, E.N., ed. Classics in Software Engineering. YOURDON Press., New York, 1979.