@article{oai:repository.dl.itc.u-tokyo.ac.jp:00041029, author = {Fujita, Takao}, journal = {Scientific papers of the College of General Education, University of Tokyo}, month = {}, note = {application/pdf}, pages = {33--46}, title = {Projective Threefolds with Small Secant Varieties}, volume = {32}, year = {1982} }