Remove \doi{}: causes pkgdown error.

Author: SebKrantz

R/methods.R

@@ -759,7 +759,7 @@ as.data.frame.dfm_forecast <- function(x, ...,
 #' VARselect(ics$F_pca[, 1:6])
 #'
 #' @references
-#' Bai, J., Ng, S. (2002). Determining the Number of Factors in Approximate Factor Models. \emph{Econometrica, 70}(1), 191-221. \doi{10.1111/1468-0262.00273}
+#' Bai, J., Ng, S. (2002). Determining the Number of Factors in Approximate Factor Models. \emph{Econometrica, 70}(1), 191-221. https://doi.org/10.1111/1468-0262.00273.
 #'
 #' Onatski, A. (2010). Determining the number of factors from empirical distribution of eigenvalues. \emph{The Review of Economics and Statistics, 92}(4), 1004-1016.
 #'