diff --git a/R/difft.R b/R/difft.R
index 252307b..6eb6f48 100644
--- a/R/difft.R
+++ b/R/difft.R
@@ -1,12 +1,23 @@
 
-#' A reference class to represent difference between twin1 and twin2
-#'
-#' @include object.R
+#' Difference between twins
 #' 
+#' A reference class to represent difference between twin1 and twin2
+#' 
+#' Difft are calculated depending on the favorable outcome chosen. It is the
+#' second level of the outcome. For example, if the outcome is 0 and 1, the
+#' favorable outcome is 1. Then, \deqn{difft_i = twin1_i - twin2_i IF T_i =
+#' 1} \deqn{ difft_i = twin2_i - twin1_i IF T_i = 0}
+#' 
+#' @include object.R
+#'   
 #' @field vt.object VT.object (refClass) representing data
-#' @field twin1 vector of \eqn{E(Y|T= real treatment)}
-#' @field twin2 vector of \eqn{E(Y|T= antoher treatment)}
-#' @field difft vector of difference between twin1 and twin2 
+#' @field twin1 vector of \eqn{E(Y|T = real treatment)}
+#' @field twin2 vector of \eqn{E(Y|T = anoher treatment)}
+#' @field difft vector of difference between twin1 and twin2
+#'   
+#' @name VT.difft
+#'  
+#' @seealso \code{\link{VT.forest}}, \code{\link{VT.forest.one}}, \code{\link{VT.forest.double}}
 #' 
 #' @import methods
 VT.difft <- setRefClass(
@@ -30,7 +41,7 @@ VT.difft <- setRefClass(
     },
     
     computeDifft = function(){
-      "Compute difference between twin1 and twin2"
+      "Compute difference between twin1 and twin2. See details."
       
       if(sum(is.na(.self$twin1)) != 0 | sum(is.na(.self$twin2)) != 0 ) stop("Twins must be valid")
       
diff --git a/man/VT.difft-class.Rd b/man/VT.difft-class.Rd
deleted file mode 100644
index 826a6f6..0000000
--- a/man/VT.difft-class.Rd
+++ /dev/null
@@ -1,27 +0,0 @@
-% Generated by roxygen2 (4.1.1): do not edit by hand
-% Please edit documentation in R/difft.R
-\docType{class}
-\name{VT.difft-class}
-\alias{VT.difft}
-\alias{VT.difft-class}
-\title{A reference class to represent difference between twin1 and twin2}
-\description{
-A reference class to represent difference between twin1 and twin2
-}
-\section{Fields}{
-
-\describe{
-\item{\code{vt.object}}{VT.object (refClass) representing data}
-
-\item{\code{twin1}}{vector of \eqn{E(Y|T= real treatment)}}
-
-\item{\code{twin2}}{vector of \eqn{E(Y|T= antoher treatment)}}
-
-\item{\code{difft}}{vector of difference between twin1 and twin2}
-}}
-\section{Methods}{
-
-\describe{
-\item{\code{computeDifft()}}{Compute difference between twin1 and twin2}
-}}
-
diff --git a/man/VT.difft.Rd b/man/VT.difft.Rd
new file mode 100644
index 0000000..1320639
--- /dev/null
+++ b/man/VT.difft.Rd
@@ -0,0 +1,35 @@
+% Generated by roxygen2 (4.1.1): do not edit by hand
+% Please edit documentation in R/difft.R
+\docType{class}
+\name{VT.difft}
+\alias{VT.difft}
+\title{Difference between twins}
+\description{
+A reference class to represent difference between twin1 and twin2
+}
+\details{
+Difft are calculated depending on the favorable outcome chosen. It is the
+second level of the outcome. For example, if the outcome is 0 and 1, the
+favorable outcome is 1. Then, \deqn{difft_i = twin1_i - twin2_i IF T_i =
+1} \deqn{ difft_i = twin2_i - twin1_i IF T_i = 0}
+}
+\section{Fields}{
+
+\describe{
+\item{\code{vt.object}}{VT.object (refClass) representing data}
+
+\item{\code{twin1}}{vector of \eqn{E(Y|T = real treatment)}}
+
+\item{\code{twin2}}{vector of \eqn{E(Y|T = anoher treatment)}}
+
+\item{\code{difft}}{vector of difference between twin1 and twin2}
+}}
+\section{Methods}{
+
+\describe{
+\item{\code{computeDifft()}}{Compute difference between twin1 and twin2. See details.}
+}}
+\seealso{
+\code{\link{VT.forest}}, \code{\link{VT.forest.one}}, \code{\link{VT.forest.double}}
+}
+