**R. Akhtar, A. Arp, M. Kaminski, J. Van Exel, D. Vernon and C. Washington**
The varieties of Bol-Moufang quasigroups defined by a single operation, pp. 1-10

**A. Ali and H. Khan**
On WIP loops, pp. 11-20

**M. Ashiq, Q. Mushtaq and T. Maqsood**
Parametrization of actions of a subgroup of the modular group, pp. 21-28

**S. E. Atani and R. E. Atani**
A Zariski topology for k-semirings, pp. 29-36

**F. N. Castro, G. L. Mullen and I. Rubio**
Some enumerational results relating the numbers of latin

and frequency squares of order n, pp. 37-52

**R. S. Gigon**
Some results on E-inversive semigroups, pp. 53-60

**N. Kehayopulu and M. Tsingelis**
On fuzzy ordered semigroups, pp. 61-70

**A. Krapez**
Varieties of rectangular quasigroups, pp. 71-80

**A. W. Marczak**
Essential operations of clones, pp. 81-85

**R. A. R. Monzo**
The spectrum of a variety of modular groupoids, pp. 87-96

**M. Shabir and R. Anjum**
Right k-weakly regular hemirings, pp. 97-112

**G. Sheeja and S. Sri Bala**
Congruences of ternary semigroups, pp. 113-124

**O. Zahiri, R. A. Borzooei and M. Bakhshi**
Quotient hyper residuated lattices, pp. 125-138

### vol.20 (2012) No. 2

**M. Akram, W. Chen and Y. Yin**
Bipolar fuzzy Lie superalgebras, pp. 139-156

**G. B. Belyavskaya**
Recursively r-differentiable quasigroups within S-systems and MDS-codes, pp. 157-168

**S. S. Davidov**
A characterization of binary invertible algebras
of various types of linearity, pp. 169-176

**I. I. Deriyenko**
Generalized IP-loops, pp. 177-182

**I. I. Deriyenko and W. A. Dudek**
D-loops, pp. 183-196

**M. K. Dubey**
Prime and weakly prime ideals in semirings, pp. 197-202

**W. A. Dudek and R. S. Gigon**
Congruences on completely inverse AG

^{**}-groupoids, pp. 203-209

**E. M. A. Elzayat**
Construction of subdirectly irreducible SQS-skeins, pp. 211-218

**R. S. Gigon**
Clifford congruences on an idempotent-surjective R-semigroup, pp. 219-232

**T. G. Jaiyeola and J. O. Adeniran**
A new characterization of Osborn-Buchsteiner loops, pp. 233-238

**N. Kehayopulu**
Left quasi-regular and intra-regular ordered semigroups using fuzzy ideals, pp. 239-249

**N. Kehayopulu**
On fuzzy ordered semigroups, pp. 251-256

**E. Leppala and M. Niemenmaa**
On finite loops whose inner mapping groups are direct products
of dihedral groups

and abelian groups, pp. 257-260

**N. A. Moldovyan and V. A. Shcherbacov**
New signature scheme based on difficulty of finding roots, pp. 261-266

**P. V. Protic**
Some remarks on Abel-Grassmann

^{,}s groups, pp. 267-274

**M. Shahryari**
Polyadic groups and automorphisms of cyclic extensions, pp. 275-281