“…For an excellent survey of almost all results up to 1974 we refer the reader in particular to book by Reissig et al [23]. Further results can be found in the books or the papers by Ahmad and Rama Mohana Rao [2], Fonda and Zanolin [4], Graef ([6], [7]), Huang et al [9], Jin [10], Kato [11], Kiguradze and Chanturia [12], Kitano and Kusano [13], Kroopnick [14], Mirzov [15], Mustafa and Tunc [16], Mustafa and Rogovchenko [17], Nápoles Valdés [18,20], Qian [22], Saker [24], Tiryaki and Ağacık [25], Tunc [26][27][28][29][30][31][32][33], Tunc and Tunc [34], Tunc and Tunc [35], Wong [36], Wong and Burton [38], Wu et al [39], Yoshizawa [40]. http://www.ispacs.com/journals/jiasc/2015/jiasc-00083/…”