What key details about sjoerd wartena can be extracted from the following bio? Bio: sjoerd wartena -lrb- born 1 may 1939 -rrb- is a retired dutch rower . he competed at the 1964 summer olympics in the coxless fours , together with jim enters , herman boelen and sipke castelein , and finished in fourth place . he won a silver medal in the coxed pairs at the 1963 european championships . son of a doctor , wartena studied literature and worked at a university library in amsterdam . in the 1970s he moved to a village in southern france , where he learned farming and in 2003 founded the movement terre de liens devoted to ecologically friendly agriculture .
- sport is rowing- caption is sipke 1963 castelein and sjoerd wartena -lrb- right -rrb- in- height is 1.89 m ftin on- club is nereus , amsterdam- birth date is 1 may 1939- weight is 76 kg lb on- image size is 300px- image is sipke castelein , sjoerd wartena , van dam 1963.jpg- birth place is amsterdam , the netherlands