An n-bit general implementation of Shor's quantum period-finding   algorithm
  The goal of this paper is to outline a general-purpose scalable implementation of Shor's period finding algorithm using fundamental quantum gates, and to act as a blueprint for linear optical implementations of Shor's algorithm for both general and specific values of N. This offers a broader view of a problem often overlooked in favour of compiled versions of the algorithm. 
J. T. Davies, Christopher J. Rickerd, Mike A. Grimes, and Durdu O.   Guney
quant-ph