1. Investigations Regarding the Measurement of the Modulation Transfer Function;Langner;Journal of Photographic Science,May-06 1963
2. Brock , G. C. Developments in our Ideas on Image Quality for Photogrammetry Jubilee Volume Dedicated to Willem Schermerhorn on his Seventieth Anniversary , I.T.C., Delft 1964
3. Brock , G. C. Study of Image Evaluation Techniques Interim Report No. 6, Itek Corporation, 1964. (Contract No. AF33(657)9158.)