diff --git a/R/close_events.R b/R/close_events.R
index a414b0b..cee2e3b 100644
--- a/R/close_events.R
+++ b/R/close_events.R
@@ -57,7 +57,7 @@ close_events <- function(data, event = c("move", "flipCard", "openTopic", "openP
 
   # remove eventIds associated with more than one trace, usually logging
   # errors that I cannot resolve
-  corrupt_eventIds <- names(which(rowSums(xtabs( ~ eventId + trace, subdata) != 0) != 1))
+  corrupt_eventIds <- names(which(rowSums(stats::xtabs( ~ eventId + trace, subdata) != 0) != 1))
   subdata <- subdata[!subdata$eventId %in% corrupt_eventIds, ]
 
   if (event == "flipCard") {
@@ -233,19 +233,19 @@ close_events <- function(data, event = c("move", "flipCard", "openTopic", "openP
 
   # fix durations that span more than one log file
   if (event != "move") {
-    tab <- colSums(xtabs( ~ fileId + trace, subdata) != 0)
+    tab <- colSums(stats::xtabs( ~ fileId + trace, subdata) != 0)
     number_logfiles <- data.frame(trace = names(tab), nlogfile = tab)
     data_wide <- merge(data_wide, number_logfiles, by = "trace", all.x = TRUE)
-    data_wide$duration[data_wide$identi == "corrupt"] <- 
-      (data_wide$nlogfile[data_wide$identi == "corrupt"] - 1) * 600000 - 
-      data_wide$timeMs.start[data_wide$identi == "corrupt"] + 
+    data_wide$duration[data_wide$identi == "corrupt"] <-
+      (data_wide$nlogfile[data_wide$identi == "corrupt"] - 1) * 600000 -
+      data_wide$timeMs.start[data_wide$identi == "corrupt"] +
       data_wide$timeMs.stop[data_wide$identi == "corrupt"]
 # TODO: This assumes that no log files are skipped
 # --> Is this assumption really valid??
   } else {
-    data_wide$duration[data_wide$identi == "corrupt"] <- 
-      600000 - 
-      data_wide$timeMs.start[data_wide$identi == "corrupt"] + 
+    data_wide$duration[data_wide$identi == "corrupt"] <-
+      600000 -
+      data_wide$timeMs.start[data_wide$identi == "corrupt"] +
       data_wide$timeMs.stop[data_wide$identi == "corrupt"]
   } # there should be no movements spanning more than two log files!