When gelation occurs due to the growth of linear
chain molecules that reticulate the universality
of the gelation transition does not completely
follow the universality class of percolation.
With D. Stauffer and D. Landau we proposed an
irreversibel growth model for kinetic gelation
as published in a
letter in Physical Review Letters Vol.49, 412-415 (1982)
showing for the first time these differences between gelation
and percolation in the ratio of the critical amplitudes.
Many more papers followed going into details and comparing
to experiments. Much insight could be gained by a simpler
model based on percolation with random interactions as
published in Phys. Rev. B, Vol. 35, p.3661 (1987).