- Netto's construction of Steiner Triple Systems
- If v is a prime number or power of the form
12t+7, then a STS(v) can be constructed from the initial
blocks
(x2i,x4t+2i+2,
x8t+2i+4), for i = 0,1,...,(2t),
where x is a primitive root of the Galois Field of order
v. (The full design is obtained by developing the full set
of initial blocks over the elements of the Galois Field.)
When v = 19, t is 1, a primitive root is 2, and
a suitable set of initial blocks is
(20, 26, 212),
(22, 28, 214), (24,
210, 216)
or
(1, 7, 11), (4, 9, 6), (16, 17, 5)
to be developed mod 19.