How should you refer to yourself in a paper? When writing a paper that discusses previous work by the same set of authors, what is the correct way to refer to it?

For example, 


  "In 2012 Fred et al. introduced a third way of resolving the washing crisis [1234]."


Should this be written 


  "In 2012 we introduced a  third way of resolving the washing crisis [1234]."


or perhaps


  "In 2012 the current authors introduced a third way of resolving the washing crisis [1234]."


or even 


  "In 2012 Fred et al. (the current authors) introduced a third way of resolving the washing crisis [1234]."


Note that in this style the reference is [1234], in case that wasn't clear.
This usually depends on whether or not you paper will be reviewed double-blind or not. If it's going to be double-blind, then you need to refer to yourself in the third person (i.e. by name, "Fred, et al.") rather than using a pronoun. If it's only going to be single-blind review, then I think it's a matter of style whether you use a pronoun or refer to yourself by name, though the venue you are submitting to, or your field, may have preferences. In which case, you should ask around.