Here are some more time travel books you may want to check out. These titles tend to be oriented toward popular science:
Time-Slip, Johannes von Buttlar, Sidgwick & Jackson, London, 1978.
Timewarps, John Gribbin, Delacorte Press, NY, 1979.
Unveiling the Edge of Time John Gribbin, Crown, NY, 1992.
Ahead of Time, Harry Harrison and Theodore J. Gordon, eds., Doubleday & Co., Garden City, NY, 1972.
Time Travel: Myth or Reality?, Richard Heffern, Pyramid Books, NY, 1977.
Time Travel, John W. Macvey, Scarborough House, NY, 1990.
Thanks to Dr. Marcello Truzzi for assistance in compiling this list.