For those who don't want to read the entire report, but would like a brief summary of the Sheffield Lake UFO sighting, here it is, from The World of Flying Saucers by Dr. Donald Menzel and Lyle G. Boyd, pp 279-280.
The sighting took place on the morning of September 21, 1958.
"Mrs. Fitzgerald "had been sitting up alone watching television and had gone to bed at the end of the late movie. The bedroom window was shut and the window curtains were closed. Outside, the night was dark; the moon had set, there were no street lights, and none of the neighboring houses was lighted.
"Lying with her arm over her eyes, trying to get to sleep, she suddenly realized that the room was illuminated and stood up on the bed to look out of the window.
"According to her account, a disk-shaped object with a hump in the middle, a dull aluminum in color, was moving across the yard at a height of about five feet. The object did not glow and did not have lights on it; she could not determine he source of the light that made it visible to her.
"About twenty to twenty-two feet in diameter and about six feet high, the UFO moved north across the driveway into a neighbor's yard, losing altitude on the way until it was only one foot above the ground. At a distance of fifty feet, it stopped and floated motionless for several seconds while pink-gray smoke billowed out from two openings in the rim and illuminated the UFO.
"Each opening contained seven pipes. The smoke did not come from the pipes but from the openings from which the pipes projected. The object then moved back into the witness's yard, rising to a height of five feet. No longer emitting smoke, it made two clockwise turns with a radius of about three feet, and rose straight up.
"The roof of the house, jutting out over the window, cut it from further view. During the entire time of the sighting, about thirty-six seconds, she had heard a muffled noise like that of a jet engine warming up. She had tried several times to waken her husband, by kicking him, but without success. When the object had gone, she went back to bed and slept."