The contents of this page (Spanish only), contributed
Velasco, describes parentesco acording to his
This excellent site includes several examples that
illustrate site alternative views of familial
relationships. The first example gives a graphical
explanation of how to calculate degrees of separation
between relatives. The second example includes the
relationship between half-siblings and
their descendants, ascendants and colateral relations.
It also includes a link that describes the Swedish
Examples 3, 4 and 6 (links to other sites) seem
to be copies of this site, without the bibliography
or due credit.