Sentence:  Several samples of citrated plasma were fractionated in our laboratory by Method 6 of Cohn <WSD>et</WSD> al . 
Meaning of the word marked with <WSD> tags:  and others ('et al.' is used as an abbreviation of `et alii' (masculine plural) or `et aliae' (feminine plural) or `et alia' (neuter plural) when referring to a number of people)