@TechReport{Blackburn_Seligman:1996,
      AUTHOR = {Blackburn, Patrick and Seligman, Jerry},
      TITLE = {What are Hybrid Languages?},
      YEAR = {1996},
      MONTH = {November},
      NUMBER = {83},
      PAGES = {19},
      ADDRESS = {Saarbrücken},
      TYPE = {CLAUS-Report},
      INSTITUTION = {Universität des Saarlandes},
      URL = {http://turing.wins.uva.nl/~carlos/hybrid/Papers/what.pdf},
      ABSTRACT = {Hybrid languages exhibit two kinds of hybridisation. First, they combine the distinguishing features of modal logic and classical logic: although they have a Kripke semantics, they also make use of explicit variables and quantifiers that bind them. Second, they don't draw a syntactic distinction between terms and formulas: terms are part of the formula algebra, thus enabling the free combination of two different types of information. The goals of this paper are to introduce a number of hybrid languages, to discuss some of their fundamental logical properties (expressivity, decidability, and undecidability), and then, brie to indicate why such systems deserve further attention. Although hybrid languages have a long and varied history, it is quite likely that most readers will know little, if anything, about them. This dictates the structure of this paper: before we can explain why we're interested in hybrid languages, we're going to have to explain what they are and give some insight into their capabilities, for only then will a discussion of broader motivational issues make much sense.},
      ANNOTE = {COLIURL : Blackburn:1996:WHL.pdf}
}