Data not yet available.
Fielder et al. (1971), Fingerman & Rao (1970), Novak & Salmon (1974), Powers (1975), Powers (1977), Rao & Fingerman (1969), Rao & Fingerman (1970), Rao & Fingerman (1975), Rao (1985), Rosenberg (2014), Salmon et al. (1978), Salmon et al. (1979), Thurman (1979)