Primer3 is a widely used program for designing PCR primers (PCR =
"Polymerase Chain Reaction"). PCR is an essential and ubiquitous tool in
genetics and molecular biology. Primer3 can design hybridization probes
and sequencing primers.

PCR is used for many different goals. Consequently, primer3 has many
different input parameters that you control and that tell primer3
exactly what characteristics make good primers for your goals.

Primer3 picks primers for PCR reactions, considering as criteria:
* oligonucleotide melting temperature, size, GC content and primer-dimer
  possibilities,
* PCR product size
* positional constraints within the source (template) sequence
* possibilities for ectopic priming (amplifying the wrong sequence)
* many other constraints.

All of these criteria are user-specifiable as constraints, and some are
specifiable as terms in an objective function that characterizes an
optimal primer pair.

manual online: https://primer3.org/manual.html

For details and citation see "References" in the package's doc folder.