Hisashi Mitsuyasu, Fukuzo Tasai, Toshiko Suhara, Shinjiro Mizuno, Makoto Ohkusu, Tadao Honda, Kunio Rikiishi,
Observations of the Directional Spectrum of Ocean WavesUsing a Cloverleaf Buoy Journal of Physical Oceanography. ,vol. 5, pp. 750- 760 ,(1975) ,
10.1175/1520-0485(1975)005<0750:OOTDSO>2.0.CO;2