The photographer is obviously Bruckert from Harvard, Nebraska.
The time frame is around 1900 - 1910.
Three children, the oldest looks like a boy about 5 years old. The next younger may be a girl about three, and the infant looks about a year old, the sex is hard to tell.
The only other clue I would have to help identify these kids is that they most likely lived in the Harvard or Eldorado area of Clay County, or around Stockham in Hamilton County. If you think you might know these children, please leave a comment!