#' @title International relations in the 90s
#'
#' @description 
#' A relational dataset recording 
#' a variety of nodal and dyadic variables on countries in the 1990s,
#' including information on conflicts, trade and other variables. 
#' Except for the conflict variable, the variables are averages
#' across the decade. 
#'
#' @format 
#' A list consisting of a socioarray \code{dyadvars} of 
#' dyadic variables and matrix  \code{nodevars} of nodal variables. 
#' The dyadic variables include
#' \itemize{
#' \item total number of conflicts;
#' \item exports (in billions of dollars);
#' \item distance (in thousands of kilometers);
#' \item number of shared IGOs (averages across the years);
#' \item polity interaction. 
#' } 
#' The nodal variables include
#' \itemize{
#' \item population (in millions); 
#' \item gdp (in billions of dollars); 
#' \item polity 
#' }
#' 
#' @source Michael Ward.
#' 
#' @name IR90s
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