Boost.Serialization custom archive linker errors

test_archive.cpp:18: undefined reference to `boost::archive::xml_oarchive_impl<my_archive>::xml_oarchive_impl(std::ostream&, unsigned int)'
xml_oarchive.hpp:87: undefined reference to `boost::archive::basic_xml_oarchive<my_archive>::~basic_xml_oarchive()'
.../interface_oarchive.hpp:63: undefined reference to `boost::archive::basic_xml_oarchive<my_archive>::save_override(boost::archive::version_type const&, int)'
.../interface_oarchive.hpp:63: undefined reference to `boost::archive::basic_xml_oarchive<my_archive>::save_override(boost::archive::object_id_type const&, int)'
.../interface_oarchive.hpp:63: undefined reference to `boost::archive::basic_xml_oarchive<my_archive>::save_override(boost::archive::object_reference_type const&, int)'
test_archive.cpp.o: In function `my_archive& boost::archive::detail::interface_oarchive<my_archive>::operator<< <boost::archive::class_id_type const>(boost::archive::class_id_type const&)':
.../interface_oarchive.hpp:63: undefined reference to `boost::archive::basic_xml_oarchive<my_archive>::save_override(boost::archive::class_id_type const&, int)'
test_archive.cpp.o: In function `my_archive& boost::archive::detail::interface_oarchive<my_archive>::operator<< <boost::archive::class_id_optional_type const>(boost::archive::class_id_optional_type const&)':
.../interface_oarchive.hpp:63: undefined reference to `boost::archive::basic_xml_oarchive<my_archive>::save_override(boost::archive::class_id_optional_type const&, int)'
test_archive.cpp.o: In function `my_archive& boost::archive::detail::interface_oarchive<my_archive>::operator<< <boost::archive::class_id_reference_type const>(boost::archive::class_id_reference_type const&)':
.../interface_oarchive.hpp:63: undefined reference to `boost::archive::basic_xml_oarchive<my_archive>::save_override(boost::archive::class_id_reference_type const&, int)'
test_archive.cpp.o: In function `my_archive& boost::archive::detail::interface_oarchive<my_archive>::operator<< <boost::archive::class_name_type const>(boost::archive::class_name_type const&)':
.../interface_oarchive.hpp:63: undefined reference to `boost::archive::basic_xml_oarchive<my_archive>::save_override(boost::archive::class_name_type const&, int)'
test_archive.cpp.o: In function `my_archive& boost::archive::detail::interface_oarchive<my_archive>::operator<< <boost::archive::tracking_type const>(boost::archive::tracking_type const&)':
.../interface_oarchive.hpp:63: undefined reference to `boost::archive::basic_xml_oarchive<my_archive>::save_override(boost::archive::tracking_type const&, int)'