var file_id = '1JqbuqOQS5NSFqfPlxJG-DY1HIW9xZl_ddjQa_F2pUv4';
var revisions = Drive.Revisions.list(file_id);
var revision = revisions.items[revisions.items.length-1];

var revUrl = Drive.Revisions.get(file_id, revision.id).exportLinks["text/csv"]  + "&access_token=" + ScriptApp.getOAuthToken();

var revString = UrlFetchApp.fetch(revUrl).getContentText();

var file_id = '1JqbuqOQS5NSFqfPlxJG-DY1HIW9xZl_ddjQa_F2pUv4';
var revisions = Drive.Revisions.list(file_id);
var revision = revisions.items[revisions.items.length-1];

// I modified following script.
var revUrl = Drive.Revisions.get(file_id, revision.id).exportLinks["application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"]  + "&access_token=" + ScriptApp.getOAuthToken();
var blob = UrlFetchApp.fetch(revUrl).getBlob();
var tempSSId = Drive.Files.insert({mimeType: MimeType.GOOGLE_SHEETS}, blob).id;
var sheets = SpreadsheetApp.openById(tempSSId).getSheets();
for (var i = 0; i < sheets.length; i++) {
  var csv = sheets[i].getDataRange().getValues().map(function(e) {return e.join(",")}).join("n");
  Logger.log(csv)
}
Drive.Files.remove(tempSSId);

var file_id = '1JqbuqOQS5NSFqfPlxJG-DY1HIW9xZl_ddjQa_F2pUv4';
var sheetIds = SpreadsheetApp.openById(file_id).getSheets().map(function(e) {return e.getSheetId()});
var token =  ScriptApp.getOAuthToken();
var revisions = Drive.Revisions.list(file_id);
var revision = revisions.items[revisions.items.length-1];
var reqs = sheetIds.map(function(e) {
  var revUrl = Drive.Revisions.get(file_id, revision.id).exportLinks["text/csv"]  + "&access_token=" + token + "&gid=" + e;
  return {url: revUrl, muteHttpExceptions: true};
});
var res = UrlFetchApp.fetchAll(reqs);
for (var i = 0; i < res.length; i++) {
  if (res[i].getResponseCode() == 200 ) {
    Logger.log(res[i].getContentText())
  }
}