I found this Mission Time Calculation for EROS flyby and Orbit manned mission
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19720006191_1972006191.pdf
A Crewed 180-Day Mission to Asteroid Apophis in 2028-2029
http://www.adrc.iastate.edu/files/2012/09/IAC-09.D2.8.7.pdf
Manned Asteroid Flyby Mission (1966)
http://www.wired.com/wiredscience/2012/05/manned-asteroid-flyby-mission-1966/
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19720006191_1972006191.pdf
A Crewed 180-Day Mission to Asteroid Apophis in 2028-2029
http://www.adrc.iastate.edu/files/2012/09/IAC-09.D2.8.7.pdf
Manned Asteroid Flyby Mission (1966)
http://www.wired.com/wiredscience/2012/05/manned-asteroid-flyby-mission-1966/