diff --git a/DESCRIPTION b/DESCRIPTION
index 531531d..3d9eab4 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,6 +1,6 @@
 Package: clinfun
 Title: Clinical Trial Design and Data Analysis Functions
-Version: 1.1.5
+Version: 1.1.6
 Depends: R (>= 3.0.0), graphics, stats
 Imports: mvtnorm
 Suggests: knitr, rmarkdown, survival
diff --git a/NEWS.md b/NEWS.md
index 04f6ae5..48a4f6a 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,3 +1,7 @@
+# clinfun 1.1.6 (12/06/2023)
+
+* moved twostage.admissible call from print method to ph2simon; added reference
+
 # clinfun 1.1.5 (10/19/2023)
 
 * clarified one-sided vs two-sided futility boundary for gsdesign functions
diff --git a/R/ph2simon.R b/R/ph2simon.R
index 621b012..75633b1 100644
--- a/R/ph2simon.R
+++ b/R/ph2simon.R
@@ -42,6 +42,7 @@ ph2simon <- function(pu, pa, ep1, ep2, nmax = 100) {
   ph2$beta <- ep2
   ph2$out <- ph2out
   ph2$nmax <- nmax
+  ph2$xopt <- twostage.admissible(ph2)
   class(ph2) <- "ph2simon"
   ph2
 }
@@ -53,7 +54,7 @@ print.ph2simon <- function(x, ...) {
   nopt <- ((1:n)[xout[,5]==min(xout[,5])])[1]
   #xopt <- xout[c(nopt,1),]
   #dimnames(xopt)[[1]] <- c("Optimal","Minimax")
-  xopt <- twostage.admissible(x)
+  xopt <- x$xopt
   cat("\n Simon 2-stage Phase II design \n\n")
   cat("Unacceptable response rate: ",x$pu,"\n")
   cat("Desirable response rate: ",x$pa,"\n")
diff --git a/man/ph2simon.Rd b/man/ph2simon.Rd
index 440039d..636b166 100644
--- a/man/ph2simon.Rd
+++ b/man/ph2simon.Rd
@@ -64,6 +64,10 @@ ph2simon(pu, pa, ep1, ep2, nmax=100)
   Jung SH, Carey M and Kim KM. (2001). Graphical Search for Two-Stage
   Designs for Phase II Clinical Trials. \emph{Controlled Clinical
     Trials}  22, 367-372.
+  
+  Jung SH, Lee T, Kim K, and George, SL. (2004). Admissible two-stage
+  designs for phase II cancer clinical trials. \emph{Statistics in
+    medicine} 23(4), 561-569.
 }
 
 \seealso{