|
| US4033050 | 1 apr 1975 | 5 jul 1977 | | Teaching machine having response dependent programming |
| US4857715 | 1 apr 1988 | 15 aug 1989 | National Computer Systems, Inc. | Overprint registration system for printing a customized survey form and scannable form therefor |
| US4937439 | 13 maj 1988 | 26 jun 1990 | National Computer Systems, Inc. | Method and system for creating and scanning a customized survey form |
| US5004896 | 26 jul 1989 | 2 apr 1991 | Educational Testing Service | Optical document scanning and mark sensing |
| US5046005 | 15 maj 1989 | 3 sep 1991 | Versatile Suppliers, Inc. | Test scoring machine |
| US5085587 | 7 aug 1990 | 4 feb 1992 | Scantron Corporation | Scannable form and system |
| US5184003 | 24 jan 1992 | 2 feb 1993 | National Computer Systems, Inc. | Scannable form having a control mark column with encoded data marks |
| US6986664 | 1 dec 2003 | 17 jan 2006 | Robolaw Corporation | Method and apparatus for improving performance on multiple-choice exams |
| US7124945 | 26 jul 2002 | 24 okt 2006 | Easy Test Co., Ltd. | Reading unit and marking card for optical mark reader |
| US7593685 | 6 jun 2006 | 22 sep 2009 | Zip-Scan, Inc. | Optical mark recognition tabulation device |
