Analysis of information sources in references of the Wikipedia article "Nikon F-401" in English language version.
[1989 releases include] Nikon F-401S/F-401S QD (N4004S/N4004S QD) [..] Upgraded F-401 [..] with ultra-fast AF even in dim light by Advanced AM200 sensor [..] [1987 releases include] Nikon F-401/F-401 QD (N4004/N4004 QD)
In 1986, [the] F-501 went on sale, and in 1987 [the] F-401 followed [..] From 1989, the AF models Nikon F-401S [..] and Nikon F-401X were successively introduced [..] Nikon F-401S [release date was] April 1989 [..] Nikon F-401X [release date was] September 1991
1991 [..] Nikon F-401X/F-401X QD (N5005)
[1989 releases include] Nikon F-401S/F-401S QD (N4004S/N4004S QD) [..] Upgraded F-401 [..] with ultra-fast AF even in dim light by Advanced AM200 sensor [..] [1987 releases include] Nikon F-401/F-401 QD (N4004/N4004 QD)
In 1986, [the] F-501 went on sale, and in 1987 [the] F-401 followed [..] From 1989, the AF models Nikon F-401S [..] and Nikon F-401X were successively introduced [..] Nikon F-401S [release date was] April 1989 [..] Nikon F-401X [release date was] September 1991
1991 [..] Nikon F-401X/F-401X QD (N5005)