[1] B"{o}hm G. Doi-Hopf modules over weak Hopf algebras. Comm Algebra, 2000, 28: 4687--4698

[2] B\"{o}hm G, Nill F, Szlach\'{a}nyi K. Weak Hopf algebras I: integral theory and C*-structure. J Algebra, 1999, 221: 385--438

[3] Brzezi\'{n}ski T, Majid S. Coalgebra bundles. Comm Math Phys, 1998, 191: 467--492

[4] Caenepeel S, De Groot E. Modules over weak entwinng structures. Contemporary Math, 2000, 267: 31--54

[5] Cibils C, Rosso  M. Hopf bimodules are modules. J Pure Appl Algebra, 1998, 28(1): 225--231

[6] Guo Q L, Wang S H. Lax group corings. Inter Electr J Algebra, 2008, 4: 83--103

[7] Turaev V G. Homotopy field theory in dimension 3 and crossed group-categories. Preprint GT, 2000, 0005291

[8]  Van Daele A. Multiplier Hopf algebras. Trans  Amer Math Soc, 1994, 342(2): 917--932

[9] Van Daele A. An algebraic framework for group duality. Adv Math, 1998, 140: 323--366

[10] Van Daele A. Multiplier Hopf algebras. Trans Soc, 1994, 342(2): 917--932

[11] Van Daele A, Wang S H. New braided crossed categories and Drinfel'd quantum double for weak Hopf pi-oalgebras.
Comm Algebra, 2008, 36: 2341--2408

[12]  Virelizier A. Hopf group-coalgebras. J Pure and Applied Algebra, 2002, 171: 75--122

[13]  Wang S H. Doi-Koppinen Hopf bimodules are modules. Comm Algebra, 2001, 29(10): 4671--4682

[14] Wang S  H. Group entwining structures and group coalgebra Galois extensions. Comm Algebra, 2004, 32(9): 3417--3436

[15] Wang S H. Cibils-Rosso's theorem for quantum groupoids. Comm Algebra, 2004, 32(9): 3703--3723