Columbia subject headings:
Navigation--Delaware River (N.Y.-Del. and N.J.)--Safety measures.
Oil pollution of rivers, harbors, etc.--Delaware River (N.Y.-Del. and N.J.)
Oil spills--Delaware River (N.Y.-Del. and N.J.)
Oil spills--Delaware River (N.Y.-Del. and N.J.)--Prevention.
Harvard subject headings:
Navigation--Delaware River (N.Y.-Del. and N.J.)--Safety measures.
Oil pollution of rivers, harbors, etc.--Delaware River (N.Y.-Del. and N.J.)
Oil spills--Delaware River (N.Y.-Del. and N.J.)
Oil spills--Delaware River (N.Y.-Del. and N.J.)--Prevention.
Princeton subject headings:
Navigation--Delaware River (N.Y.-Del. and N.J.)--Safety measures.
Oil pollution of rivers, harbors, etc.--Delaware River (N.Y.-Del. and N.J.).
Oil spills--Delaware River (N.Y.-Del. and N.J.)--Prevention.
Oil spills--Delaware River (N.Y.-Del. and N.J.).